Don't check atom labels when comparing Group Atoms.
Don't check atom labels when comparing Group Atoms.

Label checking is done as part of the isomorphism routines.
Enforcing the isSpecificTypeOf and Equivalent methods to 
check it just breaks the isomorphism routines, as demonstrated
by the two unit tests that started failing.

(Yay for unit tests!)

enochd/RMG-Py,nyee/RMG-Py,faribas/RMG-Py,comocheng/RMG-Py,enochd/RMG-Py,KEHANG/RMG-Py,comocheng/RMG-Py,pierrelb/RMG-Py,chatelak/RMG-Py,nickvandewiele/RMG-Py,nickvandewiele/RMG-Py,pierrelb/RMG-Py,faribas/RMG-Py,KEHANG/RMG-Py,chatelak/RMG-Py,nyee/RMG-Py