add Vishal's master-worker code
Merge branch 'devel' into feature/master-worker
added README for Master/Worker example
Merge branch 'devel' into feature/master-worker
Merge branch 'devel' into feature/master-worker
attempt to fix #351
Merge branch 'devel' into feature/master-worker
convert an error message into a more appropriate debug log entry
fir tcsh prompt aggression
get_exit_code in the shell adaptor now returns None if no exit code is available (instead of raising an exception)

This closes #350
remove line
Merge branch 'devel' into feature/jobid