Bug fixes

I've fixed a couple of stupid bugs in the path following of baddies, and also in some other display stuff which was just dumb.

I've also added some information to the opening screen to indicate whether you're using the accelerated euclid / curve modules (ie. cython) and also whether your system supports anti-aliasing (ie. looks pretty at all).

If your system can't do anti-aliasing I'm sorry, it's just not going to look as nice as my screenshots :-(