Updates to CSS style guide

* Some format fixes
* Some rule changes
  - quote urls
  - wrap lines at 80 chars
* Removed refs to KSS (nobody actually uses it)
Merge pull request #44 from craigcook/css-style-updates

Updates to CSS style guide
Move old docs to legacy folder, and fix some build warnings.
Add sphinx-autobuild for convenience.
First pass of rewriting/reorganizing things.