Checkin bower_components to source control

This is so builders don't have to run bower install, and also so builders and developers are sure they are using the exact same versions of dependencies.

Originally I left this out because it felt redundant but in hindsight that was a bad decision (for example, if Jenkins is building this project and doesn't run bower install, the built application will be completely broken).

Ultimately it would be good if we could tell bower to only download the files we care about for dependencies.