Use actual CDK dependencies, not cdk-bundle

[tdudgeon]

The POM file that is present on JCenter declares a dependency on org.openscience.cdk:cdk-bundle:1.5.13. It would be better to declare the actual CDK modules that it is dependent on. In my app where I'm trying to use SMSD I'm declaring the actual CDK modules that I need, and using CDK 2.3. When I add the uk.ac.ebi.smsd:sdms-* modules it pulls in org.openscience.cdk:cdk-bundle:1.5.13 which then pulls in lots of CDK 1.5.13 modules as well as the 2.3 ones I already have. It would of course also reduce bloat to not include the modules that are not needed.