Better flee runspeed calculation.

Added two new NPC special_abilities, ALWAYS_FLEE and FLEE_PERCENT.
Fixed an issue where a NPC could get stuck on a single coord in a rectangular roambox.
Added mindelay to spawngroup to allow for greater control of the roambox delay. SQL is required.

utils/sql/git/required/2014_02_26_roambox_update.sql

@@ -0,0 +1,2 @@
+alter table `spawngroup` add column `mindelay` int(11) not null default 15000 AFTER delay;
+alter table `spawngroup` change `delay` `delay` int(11) not null default 45000;