Introduce simplified html2css API

Which, now that these are implemented, lowers <style> to @media & <link rel=stylesheet> to @import.

Add bounds to all dependencies.

Normalize the license.

I decided I care more about this code getting used than whether it's aiding proprietary software.
The latter doesn't appear to be much of a threat given all other browser engines are open source.

Rename to Haskell Stylist, old name was taken.