Remove our manually tracked SASS framework.

We're attempting to track our SASS framework automatically by
using our SVN repository as a Git submodule.
Track our SASS framework from SVN.

Our SASS framework on SVN was turned into a Git submodule, to avoid
the tedious task of manually updating it when a changed is made.

Unfortunately, updating the external from SVN is a tedious three-step
process. See "Updating from SVN" section on http://bit.ly/8k8aJl
Update README file