First pass at forensic node aggregation.   Haven't done links yet.
Fix text baseline for innerLabels on circles so it's in the center.
First pass at aggregated links
Implement ungrouping functionality
Move layout manager to be a member of the graph instead of being managed by the graphView
Animate regroup.   Buggy but initially working
Make sure ungrouped aggregates get deleted in the grouping manager.
Finish nodegrouping_2