Editor. Experimenting with new blur implementation; doesn't work at present.
It's been a long time since I've worked on this. Here's what wasn't committed.
Done a lot of stuff with the editor. Not sure if I'll use it though.
Added internal barriers and changed the background to suit.
Fixed missiles clipping through external barriers.
Multiple arenas, arena selection, new shapes (which are currently FUBAR).
Fixed the external barrier and background.