[Evan] Added Skill System & Minor changes

These are Evan's changes from over break, I was worried about problems with my moving the driectories around so I am commiting them for him.

I added a very basic rudimentary skill system in Minecraft, along with the mining skill. Each skill is its own object that is located in the Skill Registry, and contains information on how much experience is given on breaking a block.

Also, I added skill managers on the server and client sides. This basically keeps track of all the players and all the skills in the world, and when changes occur, sends packets to the corresponding players. Added a PacketHandler class to create the packet to be sent, as well as a class that reads the packet. (note that this functionality could come in handy for the party system).

Also added an event handler for when a block is broken, the player receives experience and a message is sent via chat saying how much exp was gained and when the player levels up. Changed the type of event from LivingEvent to LivingUpdate event.

Minor, but added a new block called Elementium. Does nothing yet, but will be modified to be an unlockable bllock.