Additional support for list-style-type options

I've added in support for upper-roman, lower-roman, upper-alpha and lower-alpha for list-style-type on ul and ol tags.  Not sure how to test this, but if you can point me in the right direction I'd be more than happy to write them.  Everything is working great for the project I needed this for though and existing tests still pass.

I also included my previous PR into this one, just a simple requirements update in requirements.xml.

Thanks!