Update gcylc "Suite->Graph" suite for graph command changes.
Minor bug fix: initialize the dot view task_list.

Toggling the family grouping button on an empty dot view panel
(prior to starting a suite) caused a traceback.
Merge pull request #536 from hjoliver/gcylc.initialize-dot-view-task-list

Minor bug fix: initialize the dot view task_list.
Merge pull request #535 from hjoliver/gcylc.graph-command-opts

Update gcylc "Suite->Graph" suite for graph command changes.