Create a reusable item delegate wich supports "annotations".

Currently used by the QML outline and C++ type hierarchy.

Reviewed-by: kkoehne
Task-number: QTCREATORBUG-2583

src/plugins/texteditor/basetexteditor.h

@@ -648,4 +648,6 @@ private:
 
 } // namespace TextEditor
 
+Q_DECLARE_METATYPE(TextEditor::BaseTextEditor::Link);
+
 #endif // BASETEXTEDITOR_H