claim_and_run() reimplemented as a single method and single transaction; update_status() removed
the retry checking in start_over() do{} moved to top
added more (temp?) log_event calls to PipelineSetup; PipelineSetupLog now has required pid column; PipelineSetup->log_event() warns the event in addition to creating the log
next step triggering code after submission completion, along with submission updating code, all moved into a single transaction within the job run child exit watcher, so things can be properly locked down and avoid race conditions
test script and step that shows problems with database transactions: still unresolved
Merge branch 'develop' of /software/vertres/git/origin/vr-pipe into develop