Pass events around with ProcessEvent(), not AddPendingEvent().

Pass events around with ProcessEvent(), not AddPendingEvent().

The latter adds the event for later processing. As a result, the event
appears to be processed to the caller, even if the handled it was passed
to called Skip() on it. ProcessEvent() doesn't suffer from this problem,
it may modify the event as expected.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@63862 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775