* export.c (parse_export_options): New option sexp-format.
(export_seckeys,export_secsubkeys): Check sexp-format option.
(do_export): Ignore armor for sexp format.
(do_export_stream): Handle sexp-format.
(write_sexp_line,write_sexp_keyparm, build_sexp_seckey): New.
(build_sexp): New.