New file graph.py for new function skeleton_graph, for the Graph Widget.
Still not connected to the graph widget.
Fixes to skeletons_graph function.
Comparments Graph Widget now reads data from skeletons_graph.
Merge remote-tracking branch 'origin/semi2' into semi2-albert
Uncomment the requirement for a user role in skeletons_graph.
Merge remote-tracking branch 'origin/semi2-albert' into semi2