Implemented players handling
Added spawn-point slot to World
Updated DEFPACKET docstring
Fixed idiotic typo
Several changes in networking & protocol code

* Implemented maximum players control
* Refactored protocol code a bit
* Moved several settings to config.lisp
* Did some minor code improvements
Changed SEND-LOGIN-PACKETS to use position/look from player instance
Updated tasks list
Implemented time updating
Changed handshake handler to keep players after disconnect
Updated tasks list
Implemented player position and look update
Changed ADD-PLAYER in order to prevent existing player rewriting
Moved player spawn handler to specialized generic function method
Updated tasks list
Refactored some code
Implemented entities IDs
Moved map code around a bit
Implemented way of getting specified regions of map

And changed the way maps are stores from array to hashtable where key is
location of chunks column and value is chunks column itself.
Changed initialization of Chunks-column's chunks slot
Moved config.lisp to src/