working on GdkEvent.xs and GdkEvent.t

[Ross McFarland <rwmcfa1 neces com>]

just trying to avoid duplication of work.

i'm implementing setters and testing both the set and get for all of
GdkEvent structures. it's going to take a while, but once it's done we
should be able to truly synthesize events from perl. which will also
allow us to test some things that otherwise would be difficult or
impossible. 

-rm