The Seed runs where it faces

Research into why the Seed did not feel great to play: the usual numbers (acceleration, jump timing, coyote time) were already fine, but the body, the animation and the motion disagreed. Three fixes: runs now turn at a limited rate and the body faces the way it is going (no more sliding sideways through turns); reversing a run skids, leaning back, before setting off; and the Seed keeps to the ground running down slopes (before, one run down a 30 degree ramp left the ground and landed 46 times, flickering the fall pose). Air steering is stronger and the fall less floaty (gravity 1.8x on the way down). Tests cover all three.