core: Extend gpgme_user_id_t with 'address'.
* src/mbox-util.c, src/mbox-util.h: Adjust for use in gpgme. * src/Makefile.am (main_sources): Add mbox-util. * src/key.c (_gpgme_key_append_name): Set 'address' field of uid. (gpgme_key_unref): Free it.
- Signed-off-by: Werner Koch <wk@gnupg.org>