Clutter changes on trunk

["Jason D. Clinton" <me jasonclinton com>]

I will check-in these changes later today:

1. Now mandatory if Gnometris or Lights Off is built.
2. --enable-clutter dropped; if you don't want it, just disable those games
3. API moving to 0.9; this breaks everything for now. You may want to
--enable-game=whatever until clutter games build fine.
4. Clutter Cairo is now merged with Clutter
5. Our private copy of gtk-clutter-embed.h is killed off; I have no
desire to maintain it and upstream has added new features and broken
API.

For the moment, aisleriot's clutter code paths will get built if you
have one of the clutter mandatory games in your games list at
configure time. If you want to build aisleriot w/o clutter, disable
Gnometris and Lights Off. This could probably be improved somehow but
I really think having a --disable-clutter at this point would send the
wrong message to testers.