Can now handle cases where too many characteristic frequencies are found.
Can now handle cases where too many characteristic frequencies are found.

First it tries to discard hindered rotor modes to compensate. If there aren't
enough hindered rotor modes, it discards characteristic groups with the fewest
frequencies until the problem becomes underspecified again.

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