Add API games controller to return JSON game data

Our Flux JS app is going to be making requests of our API to get and
save data about games, as well as using the data bootstrapped into the
original page. I like having a separate set of routes for the restful
JSON API rather than having the single games controller do double-duty
of serving JSON and static HTML.  I think in the long run this will be
easier to maintain, and we can still reuse the JBuilder templates
between the two controllers.
Add first API routes
Add initial JS infrastructure to request game index JSON

New methods were added at every level of the JS stack to facilitate the
initial request for the game data to fill the stores.

 - In init, we will kick off the request for the game data.
 - From there we call a helper method in GameWebAPIUtils, that wraps our
   ajax requests.
 - After the ajax request completes, we pass dispatch the event via the
   Dispatcher.
 - The event is dispatched and received by the callback that the
   GameStores registered.
 - In the callback, the GameStores caches the data about all the games.
 - All of the events use strings from our GameConstants.

Next steps:
 - Bootstrap the game data into the initial page load (to save the extra
   ajax request)
 - Write the AppDispatcher to wrap helpers for handling server and view
   action dispatching.
 - Connect the rendering of the game to the GameStores data rather than
   the bootstrapped JSON in the html.