counters tests for CSS2.1 test suite

http://dbaron.org/css2.1/tests/ contains a bunch of counters tests that
I'd like to contribute to the CSS 2.1 test suite.  They should be
accurate according to the working draft published yesterday.  (And if
they aren't, there's a fair chance it's a mistake in the draft rather
than the tests.)

Also, the tests in http://dbaron.org/css2.1/tests/imported-20041214/
were imported into an internal version of the test suite back on
2004-12-14, but don't seem to be in any public version of the test suite
that I can find.

-David

-- 
L. David Baron                                <URL: http://dbaron.org/ >
          Technical Lead, Layout & CSS, The Mozilla Foundation