Update Thorax for Backbone 1.1

@kpdecker `_configure` has been removed in Backbone 1.1. This PR is tested against Backbone 1.0 and Backbone 1.1 with all tests passing. Since we have unpinned bower deps hoping we can get this in ASAP as we are looking to upgrade a few apps.

Closes https://github.com/walmartlabs/thorax/issues/261