Fine-tuned style guide base
Some minor tweaks to styles base
Added 'rem' function. 'reverse visuallyhidden' converted from a placeholder to a mixing, as the properties need to be inline with the element, not collated at the top of the stylesheet
Added 'async' attribute to js calls in head. Removed Google-hosted jQuery links. If needed, it will be put into the site's script file directly.
Added optional jQuery CodeKit import line and option to go Vanilla when possible.
Added webfontloader lib
Tweak to robots.txt