Setting default group multiplicity to [] rather than [1,2,3,4,5]

We cannot anticipate if there will be more possible multiplicities than
just these five, so we should set the default wildcard as an empty list
just like we do with radical electrons, lone pairs, etc.
Add isomorphism work in progress test for molecule and group with non-matching multiplcity
Remove reactantMatch function in data/kinetics/family.py

Seems to have been deprecated and replaced by the similar function
__matchReactantToTemplate
Perform quick checks before running findSubgraphIsomorphisms fully in molecule.py

Do this similar to the fingerprinting check in isSubgraphIsomorphic.  This
should reduce computation time.

This also ensures that multiplicity is checked between a molecule and a group.
Check multiplicity between groups when checking isSubgraphIsomorphic and findSubgraphIsomorphic
Cythonization of Group functions: isSpecificCaseOf() and isEquivalent()

This speed up mainly affects group tests.
Define a wildcard multiplicity in the group adjlist to be "multiplicity x"

Now multiplicity is defined in exactly the same syntax as unapaired electrons,
lone pairs, and charge.  This line can be omitted altogether in the group adjlist
and still represent a wildcard.

e.g. these following adjlists for Group1 and Group2 represent identical groups:

Group1
multiplicity x
1 R u0

Group2
1 R u0
Added some documentation on new wildcard representation for multiplicity in groups.
Merge pull request #320 from GreenGroup/multiplicity

Make group multiplicity wildcard more broad by eliminating [1,2,3,4,5] limitation.