Use entity UUID instead of EntityID for metadata. Fixes BUKKIT-3582

The entity id is a non-unique, non-persistent value, and will cause
entities to lose their respective meta data on chunk unloading, and
teleportation.
Set CraftTravelAgent.DEFAULT to a non-null value. Fixes BUKKIT-3578

Currently, CraftTravelAgent will call s() on the passed-in WorldServer in order to set DEFAULT. However, s() will always return null at this point, because WorldServer.P will still be null, as it is set after the constructor is called. Instead, we set CraftTravelAgent.DEFAULT to the instance that is being constructed.
Check TravelAgent.findOrCreate(Location) for null; Fixes BUKKIT-3590

If a custom TravelAgent is used and returns null for findOrCreate method
a NullPointerException will occur.
Conflicts:
	src/main/java/net/minecraft/server/PlayerList.java
Close inventory on teleport. FIXES BUKKIT-3021.
Spigot
EMC POM changes
Timings improvements
Entity Activation Range#
This feature gives 3 new configurable ranges that if an entity of the matching type is outside of this radius of any player, will tick at 5% of its normal rate.

This will drastically cut down on tick timings for entities that are not in range of a user to actually be "used".
This change can have dramatic impact on gameplay if configured too low. Balance according to your servers desired gameplay.