Push Notification hierarchy
===============

Service		org.ofono
Interface	org.ofono.PushNotification
Object path	[variable prefix]/{modem0,modem1,...}

Methods		void RegisterAgent(object path)

			Registers an agent which will be called whenever a
			new Smart Messaging based SMS arrives.

			Possible Errors: [service].Error.InProgress
					 [service].Error.InvalidArguments
					 [service].Error.InvalidFormat
					 [service].Error.Failed

		void UnregisterAgent(object path)

			Unregisters an agent.

			Possible Errors: [service].Error.InvalidArguments
					 [service].Error.Failed

PushNotificationAgent Hierarchy [experimental]
===============

Service		unique name
Interface	org.ofono.PushNotificationAgent
Object path	freely definable

Methods		void ReceiveNotification(array{byte} notification, dict info)

			Requests the agent to process a new SMS that has
			arrived containing a WAP PUSH.  The dictionary
			info contains 'Sender', 'LocalSentTime' and
			'SentTime' properties.

			Possible Errors: None

		void Release() [noreply]

			Agent is being released, possibly because of oFono
			terminating, SMS interface is being torn down or modem
			off.  No UnregisterAgent call is needed.