In case no -logic_name/-analysis_id was supplied, show the list of analyses that have no incoming dataflow (and so are candidates for seeding)

diagram improvement: (1) no more "empty boxes" and (2) tables dataflown from a box are shown in their boxes

Added coloured barchart display option and jobs/data display option (no big data checks, use with care on small examples).
'Pad' is now configurable from JSON.
Beware: JSON config options have moved around!

added command line options -submit_stdout_file and -submit_stderr_file to peek into submission output/error streams

fixed a bug in computing num_required_workers according to the new rules (thanks Matthieu for reporting)

bugfix: do not proceed with negative numbers of workers for submission (thanks to Matthieu for reporting)

fix: 'msg' view now displays the analysis of the job (which is fixed), not that of worker (which may change with time)

changed the meaning of 'num_required_workers' to "total estimated number of workers needed for this analysis" ( 'num_running_workers' is now included in it )