Less compilation and template cleanup

* Add some notes to README about things we'll have to do when
  deploying
* Install django-uni-form because one template (one!) uses it, and
  running the standalone django-compress caught the missing template
  tag library.
* Change another template to stop using the ifsetting tag, which looks
  like it used to be in Pinax somewhere, but I can't find a source for
  it anymore.
* Configure django-compressor to handle .less files
* Change site_base.html to use less*.js to compile the .less files in
  development, and django-compressor in production.