alienarena removed from games spin for F13 due to size

[Bruno Wolff III]

With the increased size of the desktop spin (upon which games is based) and
I think some game data sets getting a bit bigger it was going to be hard to
get the games spin down to size by cutting out desktop stuff. Instead for
this release I cut one of the largest games, alienarena, from the spin.
While the game will be missed, this seemed to be the best course for F13.

For F14 things look very good for getting back 10% of the games spin size
(about 400 MB) using lzma for compressing spins. That should allow me to
get alienarena back in again, barring significant increases in the size
of other games or the desktop spin.