Revise rule 26 to remove most if not all >= relationships
There are currently over 1000 >= relationiships generated by rule 26.
This occurs when Species A sec Weakley > Species B var 1 sec X
and Species A sec Weakley > Species B var 2 sec X
We want to infer relationship of Species A sec Weakley to Species B sec X
Currently we generate a >= relationship
However, the relationship should be = provided that there is no
Species B var 3 sec X that is NOT a subset of Species A sec Weakley.
This means that in almost all cases we can change the >= to = which will improve the mapping of relationships.