Guice integration

Added SelfInjectingServerResource and friends as an alternative to FinderFactory/RestletGuice.
See the [package README](
    https://github.com/Tembrel/restlet-framework-java/blob/guice-integration/incubator/org.restlet.ext.guice/README.md
) for details.

This is my first pull request; please let me know what I've missed.