Allow for environment variable CP to add to the classpath

git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1466950 13f79535-47bb-0310-9956-ffa450edef68
git-svn-id: https://svn.apache.org/repos/asf/jena/trunk@1466951 13f79535-47bb-0310-9956-ffa450edef68