GetKeyCode() instead of GetCode()
2. wxTreeEvent::GetKeyEvent()::IsAltDown() now works under MSW
3. wxTreeEvent::GetKeyCode() works for alnum keys
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@16236 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775