Convert cglib to be a maven project

Initial basis to convert cglib to be a maven project, I suspect there would be further work needed to ensure this work correctly but hopefully helps.

- Two tests were disabled for now since they relied on a signed jar file.
- Maven needs to be updated to generate sources/javadoc jar files
should this be 'provided' scope (or something else?) so that people using cglib don't depend on ant transitively?