Add .text-center utility class

I've personally found a very common use for this when developing with Ratchet.
Update jQuery to v1.11.1.
Merge pull request #550 from AlecRust/patch-2

Add .text-center utility class
Update grunt-jscs.
docs: fix /components `updateContent`.
bump grunt-contrib-csslint to ~0.3.1
Merge pull request #671 from cvrebert/master

bump grunt-contrib-csslint to ~0.3.1
bump grunt-contrib-copy to ~0.6.0
bump grunt-contrib-uglify to ~0.6.0
Merge pull request #678 from cvrebert/master

bump grunt-contrib-uglify to ~0.6.0
Update normalize.css to v3.0.2.
Update dependencies.
Travis: Update Jekyll to v2.4.0.
Switch to `grunt-sass`.
Add "grunt-banner".

We can't add a banner with "grunt-sass".