Updated to foundation 5 using foundation gem as external gem

Some updates to have working foundation 5, having foundation gem installed, I ran "foundation update" to have all dependencies in bower_components directory. By the way bower_components was inserted in .git_ignore, I don't know if this is ok.

Definitely this could be better, and new foundation gem handles updates through bower, maybe this could help to modify rake task or describe in README how to do the update with foundation gem.