Hide members of collapsed families properly in graph view.

Also renamed some misleadingly-named variables that dated back to before
we had collapsible families.
Adapt graph to recently changed var names.
Merge branch 'master' into 558.gcylc-hide-fam-members
Merge pull request #568 from hjoliver/558.gcylc-hide-fam-members

Hide members of collapsed families properly in graph view.
Don't attempt to ungroup non-family graph nodes.
Merge pull request #587 from hjoliver/586.fix-ungroup-non-fam-node

Don't attempt to ungroup non-family graph nodes.
Fix case where entire pre-initial cycle conditional eliminated.
Fix whitespace.
Merge pull request #588 from arjclark/pre-initial-fix

pre-initial cycling simplifier: fix entire conditional elimination bug