TODO

- The viewport shouldn't actually 5:3 since that's the ratio for the
  inner viewport - the HUD and border brought it up to 4:3 for the
  actual game.
- The other mob types need some love
- There's no AI
- There's no traceline function in the physics
- The rest of the pickups need to be created.
- Dead bodies
- Doors need doing. They open/close but there's no way to trigger it.
  Also I'm not sure if there's any code to spawn locked doors.
- AI Areas: There's an 'area' field on Map::Node, but nothing pays any
  attention to it.
- There's no code set up to deal with level transitions. Last I checked
  all the subsystems can deal with map loading/unloading, but there's
  nothing that keeps track of such things or could ask.
- A proper lookup system (hashmap?) for the map would be good, the current
  array<vector> setup is a bit wonk. 
- Pushwalls currently don't exist and there is absolultely nothing that
  could currently cope with them. I'm thinking point entities with a
  geometry shader?
- Sound? I was initially thinking OpenAL but that seems to be a bit shit
  on closer inspection. I haven't looked around for any alternatives but
  I'm sure they exist.
- Might be a plan to look into being able to load the sprite sheet PNGs
  the JS Wolf version uses. They may be completely different layouts but
  I recon a clever frag shader could adapt to them without very many
  changes elsewhere