Now the property browser can be docked in the same way as all other
dialogs in the Basic IDE and the Dialog Editor.
The property browser (PropBrw, for which PropertyBrowser would be a
better and easier-to-remember name IMO) is derived from
basctl::DockingWindow instead of SfxDockingWindow. PropBrwMgr was
removed (it seemed to be only a wrapper), and PropBrw is now a data
member of DialogWindowLayout (aPropertyBrowser).

Change-Id: I06737a5cbc985888432630714cb919d1bbbcbb49
Reviewed-on: https://gerrit.libreoffice.org/518Reviewed-by: Noel Power <noel.power@suse.com>
Tested-by: Noel Power <noel.power@suse.com>