Spigot had code that returned early in chunk add/remove methods.
This was causing our code added to set current chunks and counts to
be skipped over if the entity was default not persistent but made persistent.
This was the source of many issues
Fixes#1208
This enables us a fast reference to the entities current chunk instead
of having to look it up by hashmap lookups.
We also store counts by type to further enable other performance optimizations in later patches.
CraftBukkit removed their implementation that caused this issue,
switching to Mojang's implementation which doesn't appear to share it. I
already removed the important bit in the last upstream merge, this is
just unused and unnecessary now. So we remove it.
