Load Bootstrap via Bower

TODO:
- Update README
- Use grunt-bower-task?
Merge branch 'bower' into 7.0.0
Specific Bootstrap version
Load jQuery from Bower
Load Modernizr from Bower, lean build with Grunt
Better LESS organization
Ref #867 - Add Respond.js (not enqueued by default)
Gulp package set up: Sass Bootstrap, minified CSS, Jshint, Uglify and liveReload
Added config.rb
Add gulp-plumber to emit errors
fixed compass error, add gemfile and sass source map
Merge branch 'master' into gulp
add source map comment
replace master branch