code: public int compareVersions(VersionedOntology o) throws OntopException {
          if (!base.equals(o.base) || !ontologyPath.equals(o.ontologyPath)) {
              throw new OntopException("Version comparison must be done with same ontology series.");
          }
          if (major > o.major) {
              return 1;
          } else if (major == o.major) {
              if (minor > o.minor) {
                  return 1;
              } else if (minor == o.minor) {
                  return 0;
              }
          }
          return -1;
      }
docs: returns -1 if 'this' is lower than o returns 0 if 'this' is equal to o
  returns 1 if 'this' is greater than o
  
  @param o
  @return
  @throws OntopException