Introduced token caching to prevent repetetive tokenizing.

Also removed TokenUnderCursor as it's functionality is in the token cache.

Reviewed-by: ckamm

src/plugins/cppeditor/cpphoverhandler.h

@@ -36,6 +36,10 @@ QT_BEGIN_NAMESPACE
 class QPoint;
 QT_END_NAMESPACE
 
+namespace CPlusPlus {
+class TokenCache;
+}
+
 namespace Core {
 class IEditor;
 }