CppHighlighter: highlight all functions/methods.

- Highlight all function/methods (not just virtual methods).
- Highlight as a function even if number of arguments does not match. In
  that case, add a diagnostic message to indicate there are too many/too
  few arguments.
- Fix highlighting of parameters in function declarations.
  These used to be handled indiferently, and they could be mistaken for
  type or field references.
- Properly highlight template method calls.

Change-Id: I6e61c9ee47763db95c62314f9cc1c4d398df38b3
Reviewed-by: Leandro Melo <leandro.melo@nokia.com>

src/libs/cplusplus/CppDocument.h

@@ -192,6 +192,9 @@ public:
     void addDiagnosticMessage(const DiagnosticMessage &d)
     { _diagnosticMessages.append(d); }
 
+    void clearDiagnosticMessages()
+    { _diagnosticMessages.clear(); }
+
     QList<DiagnosticMessage> diagnosticMessages() const
     { return _diagnosticMessages; }