Lots of work on traction in this one, fixing several movement issues.

Here's a big cat crawling up a 35 degree slope.
Opt-in to the experimental branch to test out this update early:

Fixes
- Removed an accidental cap on gameplay camera movement refresh rate.
- Fixed attacker victory not triggering in custom battles on 'Defence' map.
Changes
- Changed the way track traction is applied.
- Overall smoother movement.
- Greatly improves hill climbing ability.
- Reduces jitter in wheels when first applying force.
- Stops vehicle slightly bending into the turn, like a motorcycle.
- Overall smoother movement.
- Commander cupolas can no longer be scaled down to points where their hatches would be unusable.
- Lowered cupola max scale from 200% to 125% of original scale. Due to clipping with commander view.
- Lowered design platform on flat sandbox map.
- Moved ramps on flat sandbox map.
- Camera tracking now gradually centres as you zoom out.
- Third person aiming now detects vehicles. The cannon will aim at the point on the vehicle under the crosshair - instead of where the crosshair is pointing at on the ground.
- Removed engine redlining camera shake.
- Hamish
Changed depots in experimental branch