an_id	IN:	AN interface identifier returned by ANstart
	annot_type	IN:	Type of the file annotation

	Purpose	Creates a file annotation.
	Return value	Returns the file annotation identifier (ann_id) if successful and FAIL (or -1) otherwise.
	Description	ANcreatef creates a file annotation of the type specified by the parameter annot_type. The file annotation identifier returned can either represent a file label or a file description.
		Valid values for annot_type are AN_FILE_LABEL (or 2) and AN_FILE_DESC (or 3).
		Use ANcreate to create a data annotation.
		Currently, the user must write to a newly-created annotation before creating another annotation of the same type. Creating two consecutive annotations of the same type causes the second call to ANcreate to return FAIL (or -1).

	FORTRAN	integer function affcreate(an_id, annot_type)
		integer an_id, annot_type