Used DefaultRexsterApplication and updated rexster.xml with latest config options.

DefaultRexsterApplication does everything that the Titan implementation used to do.  It better supported those embedding Rexster, so the old Titan specific class could be dropped.

The changes to rexster.xml allow the scriptengine to import the same classes as the Titan Gremlin Console.  Therefore classes like GeoShape and static imports like WITHIN no longer require that they be referenced by their full class name when issuing scripts to Titan Server.