Projectile fixes.

Fixes bugs from BEF:
- Shooting a moving target can pin it to the wall but leave them drifting in open space
- Shooting armour can negate embedding but not pinning.
- Scalplels and melee weapons can get embedded in wounds easily.

BEF map has significant differences to master map, so I used BEF. I'm not sure if this is a great idea, but map merging is absolutely not my forte.