Added css styleguide
Added SCSS and more details to CSS guide
Added shorthand, comments and file name change
Updated TOC list to reflect changes
Added vendor prefixes and multiple selectors
Organized into css vs scss principles. Added content on class and variable naming, selector and property order, nesting, and file structure
Merge pull request #4 from kissmetrics/ms/css_guide

Organized into css vs scss principles.
Merge pull request #6 from kissmetrics/im/css_guide

Add CSS style guide.