Bootstrap 3 support

- [x] Install bootstrap 3 using bower
- [x] Review the header
- [x] Review the breadcrumb
- [ ] Review the horizontal form
- [ ] Review the comments form
- [ ] Create a vertical form
- [ ] Review the footer
- [ ] Remove the vertical/horizontal toggle
- [ ] Use Simple Form 3 generated initializers
- [ ] Extract the wrappers configuration to Simple From

Closes #24 #26