Started switch over to c based window event handlers with backwards compatibility
Changed window_update to use cdecl where possible
Fixed bug due to options window calling update on WM_INVALIDATE
Merge branch 'c_based_window_event_handlers' of https://github.com/duncanspumpkin/OpenRCT2 into duncanspumpkin-c_based_window_event_handlers
Merge branch 'duncanspumpkin-c_based_window_event_handlers'