new LFUN_WINDOW_CLOSE

new LFUN_WINDOW_CLOSE

* LyXFunc:
  - dispatch(): transfer assertion on lyx_view_ to each LFUN on a case by case basis.
  - dispatch(): new LFUN_WINDOW_CLOSE
  - getStatus(): special treatment for LFUN_LYX_QUIT

* LyX:
  - views_, addLyXView(): deleted
  - quit(): call saveGeometry() on each LyXView before exiting.

* GuiApplication:
  - is now a QObject.
  - quitLyX(): new Qt slot for lastWindowClosed signal.

* Gui.h:
  - destroyView(), destroyWorkArea(): deleted
  - viewIds(): new method

* GuiImplementation:
  - implement above changes.
  - GuiImplementation is now a QObject
  - cleanupViews(): new private slot.
  - buildViewIds(): new helper method
  - views_ and work_areas_ are now maps of raw pointers instead of schared_ptr.

* LyXView
  - now stores its id.
  - dispatch(): special treatment for LFUN_WINDOW_CLOSE.
  - workAreaIds(): new method.
  - close(): new pure virtual method.
  - saveGeometry(): new pure virtual method.

* GuiView:
  - implements above changes.
  - GuiView(): set WA_DeleteOnClose and Qt::WA_QuitOnClose to let Qt manage the destruction on close().
  - closeEvent(): session stuff transfered to saveGeometry()

* WorkArea
  - now store its id.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@15514 a592a061-630c-0410-9148-cb99ea01b6c8