wxExtended is now wxDocking, and it's now version 1.2

To avoid a huge library, covering may different areas, most of what is currently wxExtended is now wxDockIt.

This change is make the library purpose more obvious and also to prevent it getting bloated. Also, a handfull of smaller libraries is easier to maintain development of.

The docking framework of wxExtended_1.1 has been improved and is now known as wxDockIt_1.2. The experimental wxRebar/wxCommandbar components from wxExtended were far too wxMSW specific and have been removed from wxDockIt (the source is still available in wxExtended_1.1 if you want it).

The reason for the removal of wxRebar/.. is that I intend to replace the same functionality - but on a more platform-independent basis. So expect, Rebar-type toolbars (but not just on wxMSW) as part of wxDockIt in the near future.