Matching modifiers for join

The output can collect all matches, just the first, some count of, or colelects only unmatched (diffs).  The modifier is applied to the output and does not effect either of the joined graphs.  This approach, putting modifier onto the output attachment is the intuitive place one would expect.

otherwise, output works fine, at least the console version of append. It reports all matches from join, in their proper descend and branch order. So I am almost done!