The md_list_reduced*cwl workflows are added.
md_list_reduced_2nests.cwl will chain 2 jobs,
while for md_list_reduced.cwl (currently) no
jobs are chained.

The test uses the stats logfiles (so toilcwl
must be run with --stats and --logDebug),
pulling out the lists of CWL jobs which are
run in each TOIL task.

The parent thread now pickle's toilState, passing
it to the worker thread, where it is unpickled again.

A test for completed predecessors for jobs with multiple
predecessors has been added to the worker, so that some
basic job chaining can be performed for jobs whose remaining
predecessor completes within that task.

This change does result in the parent thread not correctly
noting jobs which had multiple predecessors have now been
completed correctly. So some of the checks at the end of
the internal job routine have had to be switched off for the
moment.

…ation test.