Call Forwarding hierarchy
===============
Service		org.ofono
Interface	org.ofono.CallForwarding
Object path	[variable prefix]/{modem0,modem1,...}

Methods		dict GetProperties()

			Contains the properties for this object.

			Possible Errors: [service].Error.InProgress
					 [service].Error.NotImplemented

		void DisableAll(string type)

			Disables all call forwarding rules for type.
			Type can be one of:
				"all" or "" - Disables all rules
				"conditional" - Disables all conditional rules,
					e.g. busy, no reply and not reachable.

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

		void SetProperty(string property, variant value)

			Sets the given property value to that specified in
			call parameter.

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

Signals		PropertyChanged(string property, variant value)

			Signal is emitted whenever a property has changed.
			The new value is passed as the signal argument.

Properties	string VoiceUnconditional [readwrite]

			Contains the value of the voice unconditional call
			forwarding property.  If the value is an empty string,
			then this call forwarding rule is not active.
			Otherwise the rule is active with the string value
			as the phone number.

		string VoiceBusy [readwrite]

			Contains the value of the voice "Busy" call forwarding
			rule.

		string VoiceNoReply [readwrite]

			Contains the value of the voice "No Reply" call
			forwarding rule.

		uint16 VoiceNoReplyTimeout [readwrite]

			Contains the value of the voice "No Reply" timeout in
			seconds. The timeout can be between 1 and 30 seconds.
			Please note that it is not possible to set this
			property's value if GetProperties() has not been
			previously called or the VoiceNoReply property
			has not been set.

		string VoiceNotReachable [readwrite]

			Contains the value of the voice "Not Reachable" call
			forwarding rule.

		boolean ForwardingFlagOnSim [readonly]

			Boolean representing the voice unconditional call
			forwarding rule status.