Server now handles join messages also

* Revised as well hook documentation
Fixed issues with farmland

* Fixed farmland reversion checks not taking into account carrots and
potatoes
* Fixed #623
Fixed #626

* Fixed consumption of carrots and potatoes
Merge remote-tracking branch 'origin/master' into playerimprovements
Fixed a crash bug
Fixed #491
Partial fix for #130
Added SendMessageXXX() to cPlayer

As requested by @bearbin, one no longer needs to download a file that
links to Core. The server does it! Hopefully this encourages standards
compliance.
Pickup constructor no longer exported

It didn't do anything without Initialize() exported, anyway, pickups are
spawned with cWorld.
Added more SendMessageXXX() functions
Fixed a bunch of MSVS warnings

* Possibly also fixed some bugs with pathfinding and TNT, though
unlikely
Fixed annoying creative on fire bug
Fixed explosions bug

* Fixed bug where explosions would sometimes never be sent
Updated Core & PolarSSL
Reduced max explosions per tick
Added more chat functions
Server internally uses new functions
Improved chat messaging functions

* Moved string manipulation into cClientHandle and therefore...
+ Added configuration option for prefixes.
* Cleaned up code.
* Updated documentation for API.
Removed some unexported documentation.
Added sender name to PM if prefixes disabled

* Also moved the PVP setting into Mechanics