Gui: Implement PythonWrapper::fromQAction

Wrapping QAction through QObject does not work as QAction class
is a part of QtGui not QtCore, so Py::Object with internal
pointer being null is returned causing a crash later.
Therefore implement fromQAction conversion method.

src/Gui/CommandActionPy.cpp

@@ -59,7 +59,7 @@ Py::Object CommandActionPy::getAction()
         PythonWrapper wrap;
         wrap.loadWidgetsModule();
 
-        return wrap.fromQObject(action->action());
+        return wrap.fromQAction(action->action());
     }
     else {
         return Py::None();