ServiceRegistry: added the hide_bundle_services() method
ServiceRegistry: added the hide_bundle_services() method

This method removes the services of the bundle from the service registry dictionaries but let them be accessible using their ServiceReference.
Also, the ServiceRegistry doesn't keep a ServiceReference -> Bundle dictionary, as this information is given in the ServiceReference object.

ahmadshahwan/ipopo,tcalmant/ipopo,ahmadshahwan/ipopo