Removed a large amount of unused materials.
Map should load substantially faster and take up less disk space.

* Fixed some notable geometry precision issues
* Updated the trampoline's trigger brush to more closely match the bounds of the trampoline (you won't get launched when walking near the corners of the trampoline now)
* Updated the orientation of the info_player_start entities to match the orientations of the actual ROBLOX spawn locations
* Increased the envmap resolution on the battle armor.

Added menu thumbnail to the map.

Renamed from "crossroads" to "gm_crossroads" so that it'll show up in the menu.