Bugfix update.

The downloads have been updated.

Update contains mostly fixes and workarounds for crashes on old cards. It should display message blaming the card rather than crashing, and in some cases, even draw something nice at lower quality.
Other notable fix improves save image behaviour on some cards, and --nosound option for Arch Linux which got some weird sound issue for one of users.
Thanks to everyone who reported bugs!

So far, most of non-bugfix work is focussed on multi-player which doesn't work yet, and relevant features. I may add some single-player stuff sometime soon too, but I really would want to finish multi-player first - it seems there's more interest in multiplayer than in campaigns and other SP features. Furthermore it would make sense to design campaigns to prepare user for multiplayer.