The unit will now path to the nearest adjacent cell, drag inside, do the inner activity, then (if still alive) drag back to its original
location.
This fixes:
- Mismatch in logic between Enter and MoveAdjacentTo,
which causes an infinite loop.
- Building capturing failing from certain directions.
- Being unable to enter buildings on unpathable tiles.
- Units being stranded inside a building if the requirements
for the inner order aren't met.
