classloader that is used by Config to instantiate from JPF configured
paths. This is a standard parent-first loader to avoid multiple class
instances when using our Run*.jar tools
The main reason for having our own classloader is dynamically configured resource
and library lookup
we make it public since we add paths dynamically during JPF init
Note this is ignored according to the javadocs if the provided url is already in the classpath.
We do rely on this feature since me might add jpf.jar several times during bootstrap