1. more drag and drop and clipboard changes:

1. more drag and drop and clipboard changes:
 a) OLE clipboard works fine
 b) wxBitmapDataObject now accepts DIBs (but doesn't give them back :-( )
 c) bugs in sample corrected
2. wxFatalExit() replaced with wxFAIL_MSG() in bitmap.cpp and dcmemory.cpp
3. wxFrame::ClientToScreen and ScreenToClient() replaced with DoXXX() - like
   this, they don't hide the base class versions

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@4039 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775