New in this commit: Optimize packet writing, maybe we could even do async packet construction.
Replace the networking subsystem with a high efficient one based on Netty 4. This is currently unstable and should be used with extreme caution in production servers. Connection reliability is the only possible side effect of this commit.
In general this commit should ease the burden seen on much larger servers caused by an overabundance of threads due to the 2 thread read write system + the 3rd cleanup thread in place. By using a non blocking write architecture we can ensure that packets are dispatched as soon as possible without being queued. Chat and other async packets are managed by a dedicated thread pool, meaning there is 0 chance of any chat lag occurring. This will only be the case if no plugins are using sync chat events.
It is intended that this commit will work without any changes to plugins depending on the INetworkManager interface, however TagAPI is known to be affected.
This commit marks the end of the legacy pre 1.4 server list ping, so servers present on some server lists might want to avoid it until the server list updates.