Add classpath module location

Converts XD_HOME to expect a resource prefix. Tested with poster
and batch job. To create your own XD package with custom modules
depend on DIRT and then add modules/* to the classpath.

Add test for UrlResource and module registry

Switch to resource pattern as root for module
XD-1047: Add timeField and timeFormat to aggregatecounter

Allows the time bucket to be selected based on a field within the message.