Update build config to include cdk-testdata.
Include cdk-legacy in cdk-bundle.

This will allow builds based on 'cdk-bundle' to continue regardless as to whether classes have been moved.
Resolving some PMD warnings in MMFF atom type assignment.

Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>
Improving test coverage of MMFF atom type perception. Some code could be simplified.

Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>