preparation for allowing to use wxTimer in wxBase (heavily modified patch 1113088):

1. Changed wxTimer to use wxTimerImpl
2. Added Unix-specific generic timer implementation
3. Added wxAppTraits::CreateTimerImpl()


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@45544 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/mac/private/timer.h

@@ -0,0 +1,5 @@
+#ifdef __WXMAC_CLASSIC__
+#include "wx/mac/classic/private/timer.h"
+#else
+#include "wx/mac/carbon/private/timer.h"
+#endif