Update links (#331) - http => https

diff --git a/.clang-format b/.clang-format
index 503dfe5..cfdad2a 100644
--- a/.clang-format
+++ b/.clang-format
@@ -1,4 +1,4 @@
-# http://clang.llvm.org/docs/ClangFormatStyleOptions.html
+# https://clang.llvm.org/docs/ClangFormatStyleOptions.html
 
 DisableFormat: false
 Language: Cpp
diff --git a/doc/html_generated/roadmap.html b/doc/html_generated/roadmap.html
index 00ec0ea..791aa56 100644
--- a/doc/html_generated/roadmap.html
+++ b/doc/html_generated/roadmap.html
@@ -152,7 +152,7 @@
 - templated fixture test cases
 - test with missed warning flags for GCC
     - https://github.com/Barro/compiler-warnings
-    - http://stackoverflow.com/a/34971392/3162383
+    - https://stackoverflow.com/a/34971392/3162383
 - utf8 / unicode ???
     - https://github.com/catchorg/Catch2/pull/903
 - handle ```wchar``` strings???
diff --git a/doc/markdown/roadmap.md b/doc/markdown/roadmap.md
index ab7a364..be60304 100644
--- a/doc/markdown/roadmap.md
+++ b/doc/markdown/roadmap.md
@@ -147,7 +147,7 @@
 - templated fixture test cases
 - test with missed warning flags for GCC
     - https://github.com/Barro/compiler-warnings
-    - http://stackoverflow.com/a/34971392/3162383
+    - https://stackoverflow.com/a/34971392/3162383
 - utf8 / unicode ???
     - https://github.com/catchorg/Catch2/pull/903
 - handle ```wchar``` strings???
diff --git a/doctest/doctest.h b/doctest/doctest.h
index 7773020..89b26c5 100644
--- a/doctest/doctest.h
+++ b/doctest/doctest.h
@@ -1037,7 +1037,7 @@
 
         Result(bool passed, const String& decomposition = String());
 
-        // forbidding some expressions based on this table: http://en.cppreference.com/w/cpp/language/operator_precedence
+        // forbidding some expressions based on this table: https://en.cppreference.com/w/cpp/language/operator_precedence
         DOCTEST_FORBIT_EXPRESSION(Result, &)
         DOCTEST_FORBIT_EXPRESSION(Result, ^)
         DOCTEST_FORBIT_EXPRESSION(Result, |)
@@ -1079,7 +1079,7 @@
     //DOCTEST_GCC_SUPPRESS_WARNING("-Wfloat-equal")
 
     DOCTEST_MSVC_SUPPRESS_WARNING_PUSH
-    // http://stackoverflow.com/questions/39479163 what's the difference between 4018 and 4389
+    // https://stackoverflow.com/questions/39479163 what's the difference between 4018 and 4389
     DOCTEST_MSVC_SUPPRESS_WARNING(4388) // signed/unsigned mismatch
     DOCTEST_MSVC_SUPPRESS_WARNING(4389) // 'operator' : signed/unsigned mismatch
     DOCTEST_MSVC_SUPPRESS_WARNING(4018) // 'expression' : signed/unsigned mismatch
@@ -1161,7 +1161,7 @@
         DOCTEST_DO_BINARY_EXPRESSION_COMPARISON(<=, " <= ", DOCTEST_CMP_LE) //!OCLINT bitwise operator in conditional
         // clang-format on
 
-        // forbidding some expressions based on this table: http://en.cppreference.com/w/cpp/language/operator_precedence
+        // forbidding some expressions based on this table: https://en.cppreference.com/w/cpp/language/operator_precedence
         DOCTEST_FORBIT_EXPRESSION(Expression_lhs, &)
         DOCTEST_FORBIT_EXPRESSION(Expression_lhs, ^)
         DOCTEST_FORBIT_EXPRESSION(Expression_lhs, |)
@@ -3817,7 +3817,7 @@
 #else // DOCTEST_IS_DEBUGGER_ACTIVE
 #ifdef DOCTEST_PLATFORM_MAC
     // The following function is taken directly from the following technical note:
-    // http://developer.apple.com/library/mac/#qa/qa2004/qa1361.html
+    // https://developer.apple.com/library/archive/qa/qa1361/_index.html
     // Returns true if the current process is being debugged (either
     // running under the debugger or has a debugger attached post facto).
     bool isDebuggerActive() {
@@ -4379,7 +4379,7 @@
 
     void XmlEncode::encodeTo( std::ostream& os ) const {
         // Apostrophe escaping not necessary if we always use " to write attributes
-        // (see: http://www.w3.org/TR/xml/#syntax)
+        // (see: https://www.w3.org/TR/xml/#syntax)
 
         for( std::size_t idx = 0; idx < m_str.size(); ++ idx ) {
             uchar c = m_str[idx];
@@ -4388,7 +4388,7 @@
             case '&':   os << "&amp;"; break;
 
             case '>':
-                // See: http://www.w3.org/TR/xml/#syntax
+                // See: https://www.w3.org/TR/xml/#syntax
                 if (idx > 2 && m_str[idx - 1] == ']' && m_str[idx - 2] == ']')
                     os << "&gt;";
                 else
@@ -4406,7 +4406,7 @@
                 // Check for control characters and invalid utf-8
 
                 // Escape control characters in standard ascii
-                // see http://stackoverflow.com/questions/404107/why-are-control-characters-illegal-in-xml-1-0
+                // see https://stackoverflow.com/questions/404107/why-are-control-characters-illegal-in-xml-1-0
                 if (c < 0x09 || (c > 0x0D && c < 0x20) || c == 0x7F) {
                     hexEscapeChar(os, c);
                     break;
diff --git a/doctest/parts/doctest.cpp b/doctest/parts/doctest.cpp
index 7a8c57a..40b3a96 100644
--- a/doctest/parts/doctest.cpp
+++ b/doctest/parts/doctest.cpp
@@ -1205,7 +1205,7 @@
 #else // DOCTEST_IS_DEBUGGER_ACTIVE
 #ifdef DOCTEST_PLATFORM_MAC
     // The following function is taken directly from the following technical note:
-    // http://developer.apple.com/library/mac/#qa/qa2004/qa1361.html
+    // https://developer.apple.com/library/archive/qa/qa1361/_index.html
     // Returns true if the current process is being debugged (either
     // running under the debugger or has a debugger attached post facto).
     bool isDebuggerActive() {
@@ -1767,7 +1767,7 @@
 
     void XmlEncode::encodeTo( std::ostream& os ) const {
         // Apostrophe escaping not necessary if we always use " to write attributes
-        // (see: http://www.w3.org/TR/xml/#syntax)
+        // (see: https://www.w3.org/TR/xml/#syntax)
 
         for( std::size_t idx = 0; idx < m_str.size(); ++ idx ) {
             uchar c = m_str[idx];
@@ -1776,7 +1776,7 @@
             case '&':   os << "&amp;"; break;
 
             case '>':
-                // See: http://www.w3.org/TR/xml/#syntax
+                // See: https://www.w3.org/TR/xml/#syntax
                 if (idx > 2 && m_str[idx - 1] == ']' && m_str[idx - 2] == ']')
                     os << "&gt;";
                 else
@@ -1794,7 +1794,7 @@
                 // Check for control characters and invalid utf-8
 
                 // Escape control characters in standard ascii
-                // see http://stackoverflow.com/questions/404107/why-are-control-characters-illegal-in-xml-1-0
+                // see https://stackoverflow.com/questions/404107/why-are-control-characters-illegal-in-xml-1-0
                 if (c < 0x09 || (c > 0x0D && c < 0x20) || c == 0x7F) {
                     hexEscapeChar(os, c);
                     break;
diff --git a/doctest/parts/doctest_fwd.h b/doctest/parts/doctest_fwd.h
index dd2aef4..3db7132 100644
--- a/doctest/parts/doctest_fwd.h
+++ b/doctest/parts/doctest_fwd.h
@@ -1034,7 +1034,7 @@
 
         Result(bool passed, const String& decomposition = String());
 
-        // forbidding some expressions based on this table: http://en.cppreference.com/w/cpp/language/operator_precedence
+        // forbidding some expressions based on this table: https://en.cppreference.com/w/cpp/language/operator_precedence
         DOCTEST_FORBIT_EXPRESSION(Result, &)
         DOCTEST_FORBIT_EXPRESSION(Result, ^)
         DOCTEST_FORBIT_EXPRESSION(Result, |)
@@ -1076,7 +1076,7 @@
     //DOCTEST_GCC_SUPPRESS_WARNING("-Wfloat-equal")
 
     DOCTEST_MSVC_SUPPRESS_WARNING_PUSH
-    // http://stackoverflow.com/questions/39479163 what's the difference between 4018 and 4389
+    // https://stackoverflow.com/questions/39479163 what's the difference between 4018 and 4389
     DOCTEST_MSVC_SUPPRESS_WARNING(4388) // signed/unsigned mismatch
     DOCTEST_MSVC_SUPPRESS_WARNING(4389) // 'operator' : signed/unsigned mismatch
     DOCTEST_MSVC_SUPPRESS_WARNING(4018) // 'expression' : signed/unsigned mismatch
@@ -1158,7 +1158,7 @@
         DOCTEST_DO_BINARY_EXPRESSION_COMPARISON(<=, " <= ", DOCTEST_CMP_LE) //!OCLINT bitwise operator in conditional
         // clang-format on
 
-        // forbidding some expressions based on this table: http://en.cppreference.com/w/cpp/language/operator_precedence
+        // forbidding some expressions based on this table: https://en.cppreference.com/w/cpp/language/operator_precedence
         DOCTEST_FORBIT_EXPRESSION(Expression_lhs, &)
         DOCTEST_FORBIT_EXPRESSION(Expression_lhs, ^)
         DOCTEST_FORBIT_EXPRESSION(Expression_lhs, |)
diff --git a/scripts/cmake/common.cmake b/scripts/cmake/common.cmake
index 0ce359f..8a323ec 100644
--- a/scripts/cmake/common.cmake
+++ b/scripts/cmake/common.cmake
@@ -133,7 +133,7 @@
     # no way to silence it in the expression decomposition macros: _Pragma() in macros doesn't work for the c++ front-end of g++
     # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55578
     # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69543
-    # Also the warning is completely worthless nowadays - http://stackoverflow.com/questions/14016993
+    # Also the warning is completely worthless nowadays - https://stackoverflow.com/questions/14016993
     #add_compiler_flags(-Waggregate-return)
 
     if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0)
diff --git a/scripts/random_dev_notes.md b/scripts/random_dev_notes.md
index ce8e539..97c1c89 100644
--- a/scripts/random_dev_notes.md
+++ b/scripts/random_dev_notes.md
@@ -56,7 +56,7 @@
 https://github.com/martinmoene/catch-lest-other-comparison
 
 == how to deal with pull requests for the main branch instead of the dev branch
-- http://stackoverflow.com/questions/9135913/merge-pull-request-to-a-different-branch-than-default-in-github
+- https://stackoverflow.com/questions/9135913/merge-pull-request-to-a-different-branch-than-default-in-github
 - git fetch origin pull/ID/head:BRANCHNAME         << BRANCHNAME should be a new local branch! and then rebase it
 
 == other
diff --git a/scripts/send_to_wandbox.py b/scripts/send_to_wandbox.py
index aeacac6..f54faab 100644
--- a/scripts/send_to_wandbox.py
+++ b/scripts/send_to_wandbox.py
@@ -34,7 +34,7 @@
 
 # Strips C and C++ comments from the given string.
 #
-# Copied from http://stackoverflow.com/a/241506/627587.
+# Copied from https://stackoverflow.com/a/241506/627587.
 def strip_comments(text):
     def replacer(match):
         s = match.group(0)