Improved empty flow test
Calculate and print full flow graph before getting initial job status
Minor improvements to output
Some cleanup of old jenkinsapi support (still supported)
Renamed jobcontrol.py to flow.py
Split out set_build_result into a separate utility
Introduced parent_flow reference -
  cut down on number of arguments passed to child init
Cleanup empty flow pruning
  - empty flow discovered by the flow itself instead of parent
  - improved output