- wxDisplay is now a concrete class and uses a pImpl-based design
- got rid of four duplicate but subtly different versions of trivial
single display-only wxDisplay implementation (but 2 versions of Mac
Classic and Mac CoreGraphics implementations each still remain...)
- assorted code simplifications and memory leaks fixes
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@38127 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775