Minor improvements

A few additional tweaks to things.

• Items! They don't do anything beyond have a name, bulk, owner and position. But you can pick them up and drop them. They're currently all rendered as little purple spheres, making the game look like an overengineered, underfeatured turn-based pacman clone.
• Console commands! Swapped away from hard-coded key associations to binding keys to console strings. This isn't fully working yet, but it's looking positive.
• Better font page generation! I found some blatant stupidity in the generator which was causing different characters to be offset stupidly, causing the ugly bumpy text. Fixed it, and text now looks better.
• Coloured text! This was trivial, but it's nice to have. I also adjusted the rendering so text is somewhat softer. Although this makes it look a little blurry currently, it removes some aliasing artifacts.