NIOM - NIO Manager

Alternative to Netty
improve the existing network manager using Blocking NIO instead of IO (more effecient code)
Writes use a direct memory buffer for zero copy writes, more stable memory usage.

Reimplement Low Priority Queue
Optimized Packet PacketQueue System that supports instant send notification to the writer thread
Removed packet queue walking since it will very unlikely ever be hit now.
Writer thread will now stay asleep until it has work to do
Network threads are no longer interrupted every tick, letting them sleep as much as possible
Block Meta API

This adds an API for getting and setting PERSISTENT MetaData on a block level.

Meta is is provided in a simple Map/List setup and does not expose raw NBT access.
Chunk Save Reattempt

We commonly have "Stream Closed" errors on chunk saving, so this code should re-try to save the chunk in the event of failure and hopefully prevent rollbacks.
Keep certain items on death API

This adds a getItemsToKeep to PlayerDeathEvent that can be modified for what item a player should keep upon death.

This can be used for never-to-be-dropped items.