Cleanup the C++ front-end.

Removed CPLUSPLUS_BEGIN/END_NAMESPACE & co and made it possible to compile the parser with CPLUSPLUS_WITHOUT_QT.

src/shared/cplusplus/Token.cpp

@@ -49,7 +49,7 @@
 #include "Token.h"
 #include "Literals.h"
 
-CPLUSPLUS_BEGIN_NAMESPACE
+using namespace CPlusPlus;
 
 static const char *token_names[] = {
     (""), ("<error>"),
@@ -133,4 +133,4 @@ const char *Token::spell() const
     } // switch
 }
 
-CPLUSPLUS_END_NAMESPACE
+