Merge Matt's tim-devel changes

This is going into tim-devel, not master (yet). I'll continue to add new patches but wanted to get something remote.

Some notable changes from tim-devel as it is now:
* BaseImages#show support (though it's still missing build/push support and a couple other previously-noted things)
* Adds a missing migration from Tim
* Preliminary Backbone.js support for Tim URLs, though the actual implementation on this page is TBD.
* A few convenience methods are added to TargetImage/ProviderImage methods.

There's still plenty of work to go around, though...