Initial Vault support for economy

I personally dislike forcing our users to use a separate plugin
just to abstract different economy plugins, but sadly we live in a
hell world where there are 20 competing economy plugins and
counting so I don't want to deal with that.
Add economy reward for winning team
Economy support!

Supports any economy supported by Vault. Requires Vault plugin
installed on server.

Closes #98, ping #132, #294, #12