Update _functions.scss to add !global support.

This should not affect libsass anymore: https://github.com/sass/libsass/pull/409
not instead of == false
Merge branch 'patch-2' of https://github.com/noeljackson/foundation into noeljackson-patch-2
Merge branch 'noeljackson-patch-2'
Switch to Ruby sass, update Gemfile to Sass 3.4 and Compass 1.0, fix errors in docs CSS