Store canonical SMILES of monomer.
Store canonical SMILES of monomer.

Avoid incorrect conflict errors when a monomer is defined with a different SMILES.
PistoiaHELM/HELM2NotationToolkit,PistoiaHELM/HELMNotationToolkit,MarkusWeisser/HELMNotationToolkit,MarkusWeisser/HELMNotationToolkit