Add tabled diff view with line numbers, and line types
Add styles for step thumbnails
Add HTML structuring to step thumbnails template
Put thumbnails in a Bootstrap well
Add fullName computed alias to cast model
Refactor Step model contents into Diff model
Refactor StepThumbController contents into Step model
Correct route param naming to properly serialize URLs.
Adjust bindings in CastController to use Ember.computed.alias instead
Reorganize routes

`step` route now redirects to `diff` route with parent hash argument by
default.

Diffs may now target hashes other than the commit's parent hash if
specified manually (Probably YAGNI)
Add new and deleted file indicators.
Update to Ember Canary 11/16/13
Update font-awesome-rails from 3.2.1.2 to 4.0.3.0
Include font-awesome in asset pipeline.
Add stupid loading spinner for step loading route

Octocat head on a spinning gear
Add mousetrap-rails gem for keyboard nav
Restrict display of very large (>1000 lines) diffs
Move StepController functionality into CastController and adjust models accordingly
Add keyboard navigation between a cast's steps with left and right arrow keys