Hydrogen abstractions: added JP10rad + C3H6 to old lib
Changes to databases.
When searching for polycyclic ring correction, select correction covering most atoms

Polycylic correction should use the largest possible ring correction found.
Overrides previous usage which was to find the deepest stack, which then gave
reproducibility errors when there are two group values of the same depth and
RMG chooses the first one it finds (random).