Greatly improve the movement and avoidance code of the scientist boat ai
- Sientist boats steer smoothly instead of weaving side to side, and reliably get themselves unstuck
- Context steering uses 16 directions and steers between them instead of snapping to the nearest 45°, which caused a sawtooth style effect (even though we were lerping)
- Fixed the stuck reverse never triggering above 32fps, (it measured speed from position change between AI ticks which was 0 most frames)
- Boats back off and swing round when stalled, aground or too close to make a turn, and follow an obstacle round when they stop closing on a blocked target
- Fixed patrolling boats circling off the shore forever when their orbit point lands on land