Release v0.3

Since the last version, I've added quite a bit of content. There is now an smg and a laser death ray. You can also switch weapons using the 1-4 keys. Health pickups are also a thing, and they are implemented in such a say that makes it really easy to add new pickups. Uhhhhhhhh I don't really know if I want to keep making these because what's the point. I mean I have git history. I'll still make them, but they'll be a lot shorter. They also probably won't cover everything between updates.