Version 0.90 - July 2013

1. Allowed the 'required' field in pipeline arguments.  These arguments
now appear as required in the help messages.

2. Fixed a bug with the linkage in pipelines.  If an argument linked to
a previous argument that was itself not defined, gkno would crash.  Now
the field will be left blank and identified as a missing field later and
gkno will perform a controlled failure.
Version 0.91 - July 2013

1. Added an extra check to ensure that all pipeline arguments listed as
required are checked to ensure that they have been set.