misc. forgotten/leftover changes
* model rotational inertia for ground units; make a call
  to MoveCtrl.SetGroundMoveTypeData with key "turnAccel"
  to change per-unit behavior
  turnAccel defaults to 0.333*turnRate for all ground
  units except ships which use a more realistic default
  of 0.0333*turnRate
* make Spring.GetUnitLastAttackedPiece return piece
  number instead of piece name if called with boolean
  arg=true
* cleanup LuaSyncedMoveCtrl access to MoveType members
* other unimportant crap