Improve jparestlet with configuration options

[jgou]

It might be a good idea to add some more functionality to the jparestlet that makes it easier to integrate with forms. In the dbforms sample there is a dbforms restlet that acts as a proxy for the jparestlet, providing some sort of shielding: it decides which uri's are allowed for get/put/post/delete. Maybe we could add some configuration possibilities to the jparestlet to provide this feature.
Check also if there is other stuff that can move from the dbforms restlet to the jparestlet.

[mpo]

beyond 0.4 scope