Efficient AI please

[amylizzle]

About the PR

Gonna do some minor tweaks to flock AI to make it more efficient.

• [x] Make move only try to calculate the path once before failing.
• [x] Make move have a shorter maximum path unless you're rallying.
• [x] Check out preconditions, see if I can't make them prevent doing get_path_to with clever checks.
• [x] Look at trimming down the calls to isEnemy(), which has a ludicrous number of calls.