Bug 949779 - Modify the SMS app to use the new downsample-and-decode image feature when resizing images
Bug 974731 - Failing calendar marionette test create_event_test.js
Bug 974108 - Race condition in FxAccountsIACHelper
Queue, don't overwrite, multiple callbacks waiting on the same IAC message.
Add tests for request and callback queueing.

  Also, modify the FxAccountsIACHelper.reset method to allow the port to be
  reset between tests.