Currency v2.0, gambling, channel management, tax, and bug fixes

#44 - New and better currency system, gambling functions #6 #15 #18 #22. Refactoring of channel management #43. Donate coins to other users #42
#60 - Specific text channel chatting
#33 - Tax
#65 - Display songs in queue
#71 - Documentation and contribution guidelines

Finally the bot got some awesome new features

We have added these awesome features:

• Ability to patrol channels, let Buffbot take control and manage your channel for you.
• You're now able to play music! !play <link>
• Queue up songs for the bot to play !queue <link>
• If members of your channel is not happy with current track, they can now vote to skip to the next song in queue.. !votenext
• Coins is now implemented.. More stuff will be added to this feature as next versions evolve
• Unit tests for many commands and database functions

Please visit our wiki to learn more about these features!