Added a castor-properties file that provides a castor.properties file that configures
Castor to use the internal copy of Xerces from the JDK instead of an external copy.
This makes Castor more OSGi-friendly and the castor-properties project is an OSGi
fragment bundle for Castor. Also added org.opennms.core.* classes back to the system
classpath for Karaf.
Fixed Maven artifact for OpenNMS features.xml in opennms-full-assembly/pom.xml.
Added sonatype maven repo so that dnsjava can be downloaded for inclusion
in the karaf system folder.
Merge remote-tracking branch 'origin/master' into jira/NMS-6490-2