* src/addressbook.cpp (parse_output): New. Move the more
complex output parsing out.
(open_keyadder): Add --cms option. Send CMS certificates, too.
(Addressbook::update_key_o): Fix mem leak of user_props on error.
Add handling for CMS / SMIME.
(Addressbook::edit_key_o): Add handling for CMS.
(Addressbook::check_o): Add handling for CMS.
* src/addressbook.h (callback_args_t): Extend for cms.
* src/cryptcontroller.cpp (CryptController::resolve_keys): Add
overrides and args for SMIME.
* src/keycache.cpp (filter_chain): New. Helper to filter non leaf
certificates.
(do_update, getOverrides, onAddrBookImportJobDone, importFromAddrBook):
Handle S/MIME.
* src/keycache.h: Update accordingly.