Initial Changes to use Bootstrap 3

Note: all bootstrap 3 changes are under the `BOOTSTRAP3_PREVIEW` toggle

The purpose of this PR is to get bootstrap 3's less into production as quickly as possible so that I can start debugging end-to-end issues sooner rather than later.

This PR includes:
- addition of bootstrap 3.2.0 to `style/lib`
- addition of fontawesome 4.1.0 to `style/lib`
- decorator `use_bootstrap_3()` to be used on views that will utilize bootstrap 3's features. (Note that this will only work under the `bootstrap3_preview` toggle right now).
- a test of this decorator on the `MyAccountSettingsView`

Remember, the css changes for this view are _not_ complete. This is simply for testing end to end that the setup works. Changes will not be visible outside the toggle.