Make a CriticalPoint class, and tweak the isLinear calculations.
Make a CriticalPoint class, and tweak the isLinear calculations.

Also, we no longer average the critical point properties, but
just estimate those of the most stable resonance isomer.

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