Tweaking a few of the styles per csslint

1. Removes `.allcaps` style since it was only used in the TOS/PP (which has since moved to a legal repo).
2. Changed `background-repeat: none;` to `background-repeat: no-repeat;`.
3. Changed `-moz-user-select: none;` to the non-prefixed `user-select: none;` (since autoprefixer will add the correct vender prefixes back in).
4. Relaxed some of the noise from grunt CSSLint task.

You can run CSSLint directly using `$ grunt css csslint`. (First target converts sass to css and adds vendor prefixes. Second target runs CSSLint on the generated *.css file(s))

Closes #652