(Who Information): Ditto.
(Membership Information): Added the Text-Id type.
(modify-system-info): Fixed references to argument names in the
	error code descriptions.
(async-text-read): New async message.
(async-invalidate-text-read): New async message.
(Aux-Item Types): Don't use @field for anything but Protocol A
	structure fields.  State that allowed-content-type should be
	applied recursively to all content types.