Add method to check whether matched polycyclic group is partial match
Add method to check whether matched polycyclic group is partial match

Since this method is only used after
subgraph isomorphism check passes, it should be good
enough to detect if it is a partial match through SSSR sizing.
We cannot just check that all atoms in the cycle are matched, because we need
to match all the rings.

pierrelb/RMG-Py,pierrelb/RMG-Py