Server notifies of room activities: join, leave, and play song.
Created style for room activity feed, with dummy activities.
Updated activity feed style, removed dummy activities.
Added missing auth checking in socket.io command handler.
Added client models for activity feed.
Added templated and views for activity feed.
Merge branch 'room-activity', adding room activity feed.
Updated screenshot to show room activity feed.
Incremented version to 1.2.0-alpha.
Merge branch 'dev' at 1.2.0-alpha.

Added room activity feed.