C++: Add basic 'insert #include' quick fix.

Change-Id: I3a2fef56d6d1871ea4bbb139f9bdd2bc44dd0123
Reviewed-by: Leandro Melo <leandro.melo@nokia.com>

src/plugins/cppeditor/cppquickfix.h

@@ -36,8 +36,11 @@
 #include "cppeditor_global.h"
 #include <texteditor/quickfix.h>
 
+namespace CPlusPlus {
+class CppModelManagerInterface;
+}
+
 namespace CppTools {
-    class CppModelManagerInterface;
     class CppRefactoringFile;
     class CppRefactoringChanges;
     typedef QSharedPointer<CppRefactoringFile> CppRefactoringFilePtr;