move parserContext to its own file

This change allows us to include ast_handlers.hpp just once.

Change-Id: Ib6c70d27f79422c8b90b3006cffdb6e747ca346c
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 55e7791..2c9975e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -59,6 +59,7 @@
     src/CParser.cpp
     src/ast.cpp
     src/utils.cpp
+    src/parser_context.cpp
     )
 
 add_library(parser STATIC ${parser_SRCS})