Added prototype citeproc test suite runner.
Improved citeproc-tests:  run all tests.
Allow date-parts reading RefDate from JSON.
Revert "Allow date-parts reading RefDate from JSON."

This reverts commit 2c447ba3be4bb808297994b7acfb08f8ddb05b27.
Reference:  Improved FromJSON instances.
citeproc-tests improvemnets.
citeproc-tests improvements.
citeproc-tests: Fixed 'citations' parsing.
Reference:  More informative errors on JSON parsing.
citeproc-tests:  Allow numbers as locators.
Reference/JSON:  Allow certain fields to be either numbers or strings.
Reference:  parse date-parts with numbers instead of strings.
citeproc-tests: Skip bibliography-header entries.
Reference/JSON:  Allow more fields to be numbers.
citeproc-tests improvements.
Reference/JSON: Handle heterogenous string/number lists for date-parts.
citeproc-tests: Allow 1, 0 to be parsed as Bool.
Reference/JSON: don't require "id".
Fixed citeproc-tests.
citeproc-tests:  Remove nocase spans.