Change the include path in examples as #175 (#180)

* Change the include path in examples as #175

* Change include path in scripts
diff --git a/scripts/coverage_maxout.cpp b/scripts/coverage_maxout.cpp
index a417091..32e4616 100644
--- a/scripts/coverage_maxout.cpp
+++ b/scripts/coverage_maxout.cpp
@@ -1,4 +1,4 @@
-#include "doctest.h"
+#include <doctest/doctest.h>
 
 // helper for throwing exceptions
 template <typename T>