Give skeletons default weapons upon spawning
Fixed pitch?

Pitch of 0 should make mobs face straight. Doesn't seem to work though
=/
Added min/max underground block ranges

Replaces normal block ranges when the player is underground.
Fix concurrency issue.

HashMaps can be edited by both the main thread and extra spawn finder
threads
Stop mobs from being instantly depsawned when their limits are met
Added min/max time requirements
Don't use underground block ranges in the nether or the end