Several changes:

    - fix JWt GitModel example issue (#2719)
    - fix setDirty() for a layout that has been removed (see boards/2/topics/8555)
    - fix plain HTML (and some ajax) themes for treeview and tableview
    - implemented support for recursive event loops in libwtwihtqt (#2204)
    - WMenu: changes based on suggestions from Dmitriy