Swap places with adjacent pet (pet displacement)

[Matthew Cline]

In NetHack and several other roguelikes, if you're right next to your pet and try to move onto its square you swap places with it. That'd be real convenient in this game, instead of having to either manually tell your pet to move aside to do a dismiss-then-recall. This would also allow the pathfinding algorithm for "move to right-clicked spot" to ignore your pet.

Of course, this probably shouldn't work while in combat mode.