Corrections to comparison with Bootstrap

* Flex Video: http://getbootstrap.com/components/#responsive-embed
* NPM: https://www.npmjs.org/package/bootstrap
* Ruby Gems: http://rubygems.org/gems/bootstrap-sass
* Composer: https://github.com/twbs/bootstrap/blob/master/composer.json
Merge pull request #61 from cvrebert/master

Corrections to comparison with Bootstrap
Use direct descendents for carousel lists
Updated roadmap
Update distribution files
1.5.3
Merge from master
Add automatic vendor prefixing to JS [#66]
Add Accordion.calculate() for caching heights [#64]
Fixed changelog
Added tests for aria(), bound() and cache()
Merge branch '2.0' into 2.0-tests