include the iteration count.
(do_spki_encrypt): Removed the dummy noiv string. Use NULL
instead.
(do_spki_encrypt): Include iteration count, using sexp_uint32().
(spki_password_decrypt): New class.
(do_spki_decrypt): New function.
(make_pkcs5_decrypt): New function.

Rev: src/spki_commands.c:1.12
Rev: src/spki_commands.h:1.7