Add recognition of ACDLabs ChemSketch atom label property.

Signed-off-by: John May <john.wilkinsonmay@gmail.com>
Add reading of ACDLabs ChemSketch atom label property from V2000 molfiles.

Signed-off-by: John May <john.wilkinsonmay@gmail.com>
Relocate resource files to the cdk-io module.
Fixed up a bunch of typos/misspellings in javadoc.

Signed-off-by: John May <john.wilkinsonmay@gmail.com>
Exclude generated sources from PMD reports.
Correct PMD exclude for javacc source.