Add envify transform to watch task.
Add helper to refresh the current game with exponential backoff. See #26.
Refresh current game using the RefreshGame helper. See #26.
RefreshGame now takes a callback that is called only when the game has changed. See #26.
Refactor PlayGame a little bit.
Add a PageVisibility helper that wraps the HTML5 Page Visibility API.

See #26.
Add a configurable OperationScheduler and refactor RefreshGame to make use of it.

See #26.