Added jaxb.index, to avoid exception

org.restlet.ext.jaxb.internal.Marshaller$1 initialValue: Problem
creating Marshaller
javax.xml.bind.JAXBException: Provider
com.sun.xml.bind.v2.ContextFactory could not be instantiated:
javax.xml.bind.JAXBException: "de.micromata.opengis.kml.v_2_2_0" doesnt
contain ObjectFactory.class or jaxb.index
 - with linked exception:
[javax.xml.bind.JAXBException: "de.micromata.opengis.kml.v_2_2_0" doesnt
contain ObjectFactory.class or jaxb.index]