Use GNU parallel to manage loops
Merge branch 'unstable' into more_parallel

Conflicts:
	src/do_difference_workflow.sh
Adjust parallel jobs allocation
Use global variable

One of the variables in a function exported to GNU Parallel was not
itself exported.  Pathing woes ensued.

Signed-off-by: Alex Nelson <a.nelson@prometheuscomputing.com>
Escape ampersands too
Slightly modularize error counting
Merge branch 'more_parallel' into unstable

Conflicts:
	src/do_difference_workflow.sh

The validating-Fiwalk steps caused the conflict.  Easy resolution.