Fix issue with mac key handling

git-svn-id: http://svn.wxwidgets.org/svn/wx/wxPython/3rdParty/Editra@73710 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Fix keyboard handling issues on OSX (Shift+Delete)

git-svn-id: http://svn.wxwidgets.org/svn/wx/wxPython/3rdParty/Editra@73711 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775