Fixes for point group calculation.

These should prevent the crash at the first attempt.
Should now make a few attempts to calculate the point
group, then if that fails, it should go to the next qm
calculation option. If all else fails, it will go back to
group additivity.
Tweak to symmetry logging. See issue #130
More informative logging for InChI mismatch after running QM.
Changing what ZPE is read for compound methods

This commit changes what ZPE is read in for compound
methods like CBS-QB3 and G3.

Cantherm now reads in
E (0 K) which is E_elec + scaled ZPE
It then calculates E_elec = E (0 K) - E(ZPE)

Later it calculates the ground state energy as
E0 = E_elec + unscaled ZPE * scaling factor from input file.

This is done so to be consistent when we use different method/basis
for energy and frequency calculations (ex F12 jobs). It also
puts the onus on the user to suply the correct scaling factor for
the method.

Note: The loadZeroPointEnergy() still reads in the unscaled ZPE

closes issue #132
Merge branch 'master' of github.com:GreenGroup/RMG-Py
If QM fails for 1 resonance isomer, use the one that works
Better way to fix the resonance isomer QM problem
Debug help when parsing mopac log files.

Trying to help issue #134.
This is unlikely to fix anything, but should help debugging.
Write the QM thermo entry to libray only if QM calculation was successful.
Do not fail when QM attempt is unsuccessful in Gaussian.

Return None for thermo so that that it can fall back to group additivity, same
as for Mopac.
Fixed bug for QM when no thermo found for radical.
Merge branch 'master' into 'QMts'