Add a class solely devoted to displaying cards.

Also includes a new, better named Card class that is stripped of all
the view/display related code that the old one had.
Refactor CardExtractor to use updated Card class.

Clean up the CardExtractor code a little and have it return a list of
the new card class.  This means we need the main script to properly
pass these along to the CardRenderer for display.  The old card tests
were not really doing anything important, so they were deleted.
Update html data to the latest from the site.
Fixup return value.
Setup.cfg configured for "nosy" test runner.
Python 3 compatibility.
The module cssselect is now separate from lxml.