* Protocol: update Abilities flags
+ Add Spectator handling
* BioGen: move <iostream> include
* ClientHandle: rename Respawn packet dimension check flag
* Make it clearer what it's doing.
* ClientHandle: move ProcessProtocolIn calls to World
* Player: remove some redundant initialisation
* Player: UpdateCapabilities enables flight for spectators
* Produce growth: improve comments
* ClientHandle: run unload checks using delta time
* Fix forgotten initialisation of time member
Tiger Wang