update to Bootstrap 3.2.0

- use CDN link to take advantage of people who may have cached version of Bootstrap already
- use minified version for faster loading
- remove old Bootstrap files
update to Font Awesome 4.1.0
add Gemfile

for easier and more consistent local dev environments
Merge pull request #31 from janzelc/update-bootstrap-3.2.0

Update Bootstrap to 3.2.0 and Font Awesome to 4.1.0