adds initial 'white vs black 10/5' message to Chat
starts merging Lightsquare templates into a single Ractive template - header merged in as a partial
starts implementing Promises in User.  removes NeededInGame and GamesReceived.  adds
getGame and getGames, both returning Promises.
starts refactoring Lightsquare to use Promise based system for loading games.
removes handler for GamesReceived; listens to NewGame with an id parameter.
Passes an id to GamePage instead of a Game; GamePage will be modified to use
User.getGame which returns a promise.  That way it can display an error message
when the promise fails.