Bugfix and use of environment at object creation time

Prevent occasional hangs (especially) if first command was lg on a small group.

Ensure the harness is started at obejct creation time so that igroupadmin will inherit environment of that scope (rather than later at time of first method call).
More thorough parsing of lg output

remove 'No rows found' when no results
croak on not finding "Members of group" when asking for a groups membership