Revert "solve compile failed in larger 3.0.0, lua-5.1 (closes #122)."

[solemnwarning]

This reverts commit bde906e39b19f5179c66c44c9b681f40bf4475e0.

I'm not sure what the original problem this was trying to resolve, but moving the wxDEFINE_EVENT macros into wxlstate.h duplicates the event definitions and leads to different translation units having different IDs for the same events.