Work on upgrading to upcomming 3.0.0 release

This commit contains Bootstrap 3.0.0.RC2

I have added a few notes about upgrading since it is not directly compatible.

Typeahead javascript has been removed from bootstrap, but I have created a plugin
for Twitter Typeahead.js as replacement.

Icons are now also in a seperate project (http://glyphicons.getbootstrap.com/), but I'm not sure if we should
include them in the twitter-bootstrap grails plugin or create a seperate one. Thoughts?