Make AggressiveAI respond to being hit

Since we don't know what hit it, we can increase the agro timer.  That
way if the enemy was not in an agro state, nearby enemies won't be set
to agro by one enemy being sniped, and you can avoid making it agro by
not going near it when it's in its aware state.
ActiveAI now reacts

ActiveAI only becomes agro if another nearby enemy is agro, or when it's
hit and the player enters its agro range.  It does not go agro just by
stepping within its agro range like the AggressiveAI, it needs
preexisting conditions to exist before it becomes aggressive.  It also
does not attack as frequently.

Also some optimizations were made to some of the calls AggressiveAI
makes
Merge branch 'AI' of https://github.com/nhydock/revert into AI
Enemy typing is set on construction

Also did some src formatting