Fix Massive Memory Leak

Pathfinder objects are storing references to ChunkCache's, and never cleaning up.

These ChunkCache's then leak other entity objects. Those entity objects then have leaks to their
own chunk cache. A recursive problem....

Clean up the ChunkCache reference after it is done being used.

importmcdev.sh

@@ -54,6 +54,7 @@ import PacketPlayInResourcePackStatus
 import PacketPlayOutPlayerListHeaderFooter
 import PacketPlayOutTitle
 import PacketPlayOutUpdateTime
+import PathfinderAbstract
 import PathfinderGoalFloat
 import PersistentVillage
 import TileEntityEnderChest