At least check inside the CML node for molecule

CML can have a molecule node as the root element, or a cml node
containing one or more molecule nodes. Add a small piece of logic to at
least look within the cml node for the first molecule.

Change-Id: Ie6ff59efc85edb05286237dd9cb3c9e635348e53
Merge topic 'cml' into master

b1adf15d At least check inside the CML node for molecule