voting from HTML5 player

@rynothebearded wants to add the capability to vote on tracks from the 'HTML5 player' in Pintsize.
- No authentication, no recording of the IRC name.
- New vote table columns:
  - channel: IRC channel, 'privmsg', or 'web'
  - source IP address
  - source IP address reverse DNS lookup
- Votes from HTML5 player count for -1 or +1
- Player says "votes count more if you vote from the IRC channel"
