This patch introduces a new flag that later on will help to solve the problems with aromaticity in CDK.
The flag is called SINGLE_OR_DOUBLE and the thought is that it will be used for marking uncertainty of the bond order.
If it's used on an IMolecule it means that one or several of the bonds have this flag raised (which may indicate aromaticity), on a IBond it means that it's unclear whether the bond is a single or double bond and on a IAtom it is a way for the Smiles parser to indicate that this atom was written with a lowercase letter, e.g. 'c' rather than 'C'.
The patch also contains changes in the SmilesParser-class that implements the use of this flag and a test class for testing the changes.