2 - removed pf_sample from library - this was test code
3 - modified newbmpbutton to create all button images once at initial
creation
4 - newbmpbutton only refreses when necessary
5 - non-msw platforms may now disable (enable(FALSE)) a button - this will half-grey the image and draw text in disabled color.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@1941 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
