All done with the pom for now.
Removed the ability to add properties to a DocumentRoot.

This allowed us to remove the property type parameters from all over. We could also add name type parameters to the literals. The resulting APIs are vastly cleaner and there are fewer magical casts.
Merge branch 'feature/documentation010' of github.com:drdozer/sbol-data into feature/documentation010
Merged and fixed javadoc