Add the comparison of substructure at primitive and object levels.
Add a test suite to test it.
	new file:   SmGrConfMatrix.py
	modified:   evallg.py
	modified:   lg.py
	new file:   smallGraph.py
	modified:   sumMetric.py
	modified:   testlg.py

	new file:   Tests/segment1sc
	new file:   Tests/segment2sc
	new file:   Tests/segment3sc
	modified:   lg.py
	modified:   testlg.py