Added sv_jump_precision_enable 0 to the cfg (thanks Valve)

Fixed skybox clipping.

- Renamed zone triggers to the following, as per the naming convention[github.com]:
- Stages are now s1_start to s8_start, and the end is map_end.
- Bonus is b1_start and b1_end.

- Shrunk the end teleport by a tiny amount to prevent false finishes.

Created surf_ace.