[C++] Rewrite of the preprocessor.

This rewrite fixes a couple of issues with the pre-processor. It now
supports:
- macros in macro bodies
- stringification of parameters [cpp.stringize]
- the concatenation operator [cpp.concat]
- #include MACRO_HERE
- defined() inside macro bodies used in pp-conditions.

Change-Id: Ifdb78041fb6afadf44f939a4bd66ce2832b8601f
Reviewed-by: Roberto Raggi <roberto.raggi@nokia.com>

src/libs/cplusplus/FastPreprocessor.h

@@ -69,7 +69,6 @@ public:
     virtual void startExpandingMacro(unsigned,
                                      const Macro &,
                                      const QByteArray &,
-                                     bool,
                                      const QVector<MacroArgumentReference> &) {}
 
     virtual void stopExpandingMacro(unsigned, const Macro &) {}