[Enhancement] MobStack support

[TerdyTheTerd]

MobStack is a plugin that stacks mobs to prevent lag from entity cramming/AI calculations. It's essential on my server to prevent mob grinders from lagging the server. I would love to see support between this plugin and that one, as currently this plugin reads the stacked mob as a single mob, rather than the stack size (say there's 5 stacks of 30 mobs, I would like to prevent any more mobs from entering that chunk and stacking, but right now it only see's those 5 stacks of mobs as 5 single mobs).