There should be an option to use html5lib instead of lxml.html in DjangoClient (chokes on some html5 input)

It looks like libxml2's html parsing doesn't produce a proper html5 DOM and sometimes chokes on valid html5 even when run in tolerant mode which can result in errors like "XMLSyntaxError: ... Tag footer invalid". The solution is probably to allow the usage of html5lib instead. One hitch with this is the methods from HTMLMixin no longer exist, so the dependence on these should be removed from Splinter.

Start by locating DjangoClient and its use of HTMLMixin, then trace how parsed HTML is consumed. Add an option for html5lib parsing, remove the dependence on HTMLMixin methods, and verify that valid HTML5 such as footer elements no longer causes parsing errors.

Written by the indexing model from the issue text.