Frictionless thruster physics. Next commit should be a synthesis of these kinematics with the initial sketch. Some more constants added.

Signed-off-by: Bjorn Westergard <bjornwestergard@Bjorns-MacBook-Pro.local>
Added "skating" factor, debug velocity indicators.

Signed-off-by: Bjorn Westergard <bjornwestergard@Bjorns-MacBook-Pro.local>