Update CDK version from 2.11 to 2.12 in README
Updated the GitHub Actions
Bumped the year
Reduce the occurrences of "extends CDKTestCase" many times this is not needed at all and allows us to remove "test-jar" dependency.
Implement the option "EXPAND_HYDROGENS" we do this as a preprocessing step before the transform is run.
Allow abbreviations with isotopes, for example CD3 for deuterated methyl.
Remove commented code
Ensure small ring size check work correctly.