Create BootstrapFormBuilder.

- Create subclass BootstrapHorizontalFormBuilder.
- Update Devise forms to use custom form builders.

Current spec status: 44 examples, 0 failures in 0.35677 seconds.
Add Bootstrap icons to form validation states.

Current spec status: 44 examples, 0 failures in 0.38468 seconds.
Merge pull request #5 from sleepingkingstudios/feature-authentication

Create Bootstrap form builders, update authentication forms.