[Enhancement] Add with-java-uris option for OWL2Java Vocabulary generation using java.net.URI type

[lukaskabc]

This PR adds an option that enables the generation of Vocabulary class fields using the java.net.URI type.

The generated fields will use u_ prefix (as URI).
So, it is possible to use this option alongside the OWL-API IRI fields generation, and the generated Vocabulary class is backwards compatible.

Configuration option for Maven plugin: with-java-uris
CLI parameter: -u

The resulting Vocabulary class with both options enabled (with OWL API and with Java URIs):

import java.net.URI;
import org.semanticweb.owlapi.model.IRI;


/**
 * This class was generated by OWL2Java 2.4.4
 * 
 */
public class Vocabulary {

    public final static String ONTOLOGY_IRI_OWL2JAVA_ICS_DOT_OWL = "http://krizik.felk.cvut.cz/ontologies/owl2java-ics.owl";
    public final static String ONTOLOGY_IRI_OWL2JAVA_ONTO_DOT_OWL = "http://krizik.felk.cvut.cz/ontologies/owl2java-onto.owl";
    public final static String s_c_Thing = "http://www.w3.org/2002/07/owl#Thing";
    public final static IRI c_Thing = IRI.create(s_c_Thing);
    public final static URI u_c_Thing = URI.create(s_c_Thing);
    public final static String s_c_Agent = "http://krizik.felk.cvut.cz/ontologies/owl2java-onto.owl#Agent";
    public final static IRI c_Agent = IRI.create(s_c_Agent);
    public final static URI u_c_Agent = URI.create(s_c_Agent);
   // ...
}

[ledsoft]

LGTM, thank you!