RACE: New models for race pacemaker

[deurk]

The shaft trail works well, and it probably the best asset right now to generate a path, but I think adding a simple cube (or maybe taking the ones from end of e1m2) would work better.

Jump indicators has got to be something different than nails as well to make them more visible, and be positioned on the floor.

Might add a firing indicator as well for races that allow it.