Added lots of stuff (hope I won't be sued for this :)
* Basic track objects in .OBJ format (some of them need re-exporting, some of them still missing)
* Horizon images scaled up
* Default game track
* Three.js library & add-ons
* Demo loading a track (big hairy switch, crappy and could be fixed using a map in almost all cases) and navigation using mouse & WASDRFQE