Games update

Announcing the games update (2.5.0)!

Since the introduction of the interactive stories in version 2.1.0,
we've noticed the accumulation of tokens without much use for them.
This update overhauls the story system to bring you two new important features:

• We've added Blackjack and Texas Hold 'em to Beymax. Use the !bid command to
  start a session of either
• Games (including interactive stories) now support multiplayer. Use !invite
  to add a player to your game

One other quick note is the addition of timers. Use !timer to start a timer

==========

All changes

• Refactored story system to handle arbitrary games using an event-based api. Expect new games soon
• Enabled multiplayer games using !invite, !join, and !leave
• Added a Poker system. Currently this system supports Blackjack and Texas Hold 'em
• Added !invite, !join, and !leave commands to handle multiplayer games
• Reordered the !_payout command to be more readable:
  !_payout {user} {amount} {type}
• Added !timer and !coinflip commands
• Enabled forwarding error messages to the bugs channel (can be disabled via configuration)