Move years from subheading to end of heading (in parentheses)

I replaced the optional subheading with a placeholder, "subheading",
which will be filled with the number of authors in each group in the
following format: ### / 4390 (##%).
Display the number of authors in subheading of each chart

The subheading shall then be completed with the total of all authors
and the percentage of authors in the chart, for reference.
Rename variable totalAuthors to totalAuthorsInChart
Including total authors and percentage for reference in subheading
Replace "All AR" with "Any of All AR" in an attempt to clarify
Merge branch 'enhancements'
Merge branch 'master' into gh-pages