SCXML - The Repository Path resolver was implemented wrong

The current implementation, RepositorySCXMLRegistry.RepositoryPathResolver was implemented with wrong assumption.

As javadoc says, PathResolver is basically responsible for translating the (URL) path which is normally read from 'src' attribute (e.g, <invoke/>) into a physical URL. For example, "/a/b/c.xml" --> "http://localhost:8080/a/b/c.xml" or "file://base/path/a/b/c.xml".

So, the interface is totally unrelated to XML Include or something similar.
With the current specification, it's only meaningful for <invoke src="url"/> now.

Therefore, I think we can just use the built-in URLResolver instead.