Add group_name to arguments

Also unify the public attrs that were added in CLIArgs
but not added to the base class.  In general, all public
interfaces need to be defined in the base CLI class to
make it clear what subclasses need to implement.
Add extra test for boolean arg merging
Merge branch 'merge-bools' into develop

* merge-bools:
  Add extra test for boolean arg merging
  Add group_name to arguments