Parties fixed + New Party code

[Admins]

We have fixed the party commands, so now the name doesn't need to be lower case and you can use the commands /party leave, /party who etc. When you form a party then it is automatically joining you to the party.

Also the parties now calculate the exp gain differently. There is no level cap right now, the exp is based on each players level divided by the number of players in the party. We might need to change the experience gain for low level players though.