use django-compressor to minify our js and css

django-compressor is pretty clever, and lets us leave the js/css in
the html, rather than having to move it to files first. A simple
modification to the base template catches most of the js and css we
use. Some refinement will be needed, but this is already pretty good.
compress some more js blocks
remove manual cache busting

django-compressor uses the hash of the file contents, so any change
changes the url automatically.
fix some syntax errors in stylesheets
move templated data out of the compressed JS

base.html uses a block called jsdata that can be used to add
additional uncompressed javascript code; this should be limited to
only that data which is unique to the current request or user.
Merge pull request #10 from solarpermit/minification-django-compressor

[wip] Minifiy JS/CSS using django-compressor