CppParser: fix compilation warnings

Fix the following warnings:

../../../src/CppParser/CppParser.cpp: In destructor ‘CppSharp::CppParser::ParserResult::~ParserResul
t()’:
../../../src/CppParser/CppParser.cpp:49:12: warning: possible problem detected in invocation of dele
te operator: [enabled by default]
     delete Parser;
            ^
../../../src/CppParser/CppParser.cpp:49:12: warning: invalid use of incomplete type ‘struct CppSharp::CppParser::Parser’ [enabled by default]
In file included from ../../../src/CppParser/CppParser.cpp:8:0:
../../../src/CppParser/CppParser.h:73:8: warning: forward declaration of ‘struct CppSharp::CppParser::Parser’ [enabled by default]
 struct Parser;
        ^
../../../src/CppParser/CppParser.cpp:49:12: note: neither the destructor nor the class-specific operator delete will be called, even if they are declared when the class is defined
     delete Parser;
            ^

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@iki.fi>

src/CppParser/CppParser.cpp

@@ -6,6 +6,7 @@
 ************************************************************************/
 
 #include "CppParser.h"
+#include "Parser.h"
 
 namespace CppSharp { namespace CppParser {