Tracked down several issues with entity replication.
 - Fixed the block entity system wiping network ids of persistent blocks
 - Fixed existing entities not being registered with the network system correctly on world load
 - Fixed the sending of null entity updates when an entity is destroyed
Tidied up some seralization code.
Added more logging around network events, and around misuse of add/save componet.
Improved PojoEntityRef.toString() to include network id if present, and added a toFullDescription() method for writing an entire entity to a string.
Fixed console focus and closing
Added support for HOME and END keys in UIText to go to the start and end of input
Improvements to Join Server menu - including no longer crashing the game if the server cannot be connected to.
Removed some forward references into modules.
Initial work on disconnect handling. When a player disconnects the server now removes their client and client info entities.
Also fixed an issue with the calculation of net-ticks.
Unified handling of local-only and net players.