test-citeproc improvements.
test-citeproc improvements.

You can specify a command-line argument which will match tests.
Multiple arguments work disjunctively.

Also, we now strip off the

.. [0]

or

>> [1]

that citeproc is expecting when "citations" is used.  This helps get
at the tests we care about.

jgm/pandoc-citeproc,jkr/pandoc-citeproc,adunning/pandoc-citeproc