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/SymbolVisitor.cpp

@@ -49,7 +49,7 @@
 #include "SymbolVisitor.h"
 #include "Symbol.h"
 
-CPLUSPLUS_USE_NAMESPACE
+using namespace CPlusPlus;
 
 SymbolVisitor::SymbolVisitor()
 { }