gst/games/gstpuzzle.c: - handle nav events differently: forward every event no matter if it was handled or not.

Original commit message from CVS:
* gst/games/gstpuzzle.c: (nav_event_handler):
- handle nav events differently: forward every event no matter if it
was handled or not.
- translate events
You can now cheat by using navigationtest ! puzzle and moving the
mouse close to the edge of a tile. ;)