Some Physics Tweaks

Fixed a regression that caused the avatar to panic link while flying around.

Tweaks for some things that appear to be different in PhysX 2.6.4 (compared to 2.6.0, which Skoader's changes were designed for).
- Create the physical controller at -2,000ft initially to encourage initial footstep regions to fire. They did not in the cleft.
- Bump the step offset slightly so we don't get stuck on surfaces that appear to be flat