* scd/app-common.h (struct card_ctx_s): New.
(struct app_ctx_s): Factor card specific fields out to card_ctx_s.
(app_get_slot): New.
* scd/scdaemon.h (card_t): New.
(struct server_control_s): Rename field app_ctx to card_ctx and change
all users.
* scd/app-dinsig.c: Use app_get_slot and adjust for chang in card
related fields.
* scd/app-geldkarte.c: Ditto.
* scd/app-nks.c: Ditto.
* scd/app-openpgp.c: Ditto.
* scd/app-p15.c: Ditto.
* scd/app-sc-hsm.c: Ditto.
* scd/app.c: Lost of changes to adjust for the changed data
structures.  Change all callers.
(app_list_lock): Rename to card_list_lock.
(app_top): Remove.
(card_top): New.
(lock_app): Rename to lock_card and change arg type.
(unlock_app): Rename to unlock_card.
(app_dump_state): Print card and app info.
(app_reset): Rename to card_reset.
(app_new_register): Change for the new data structure.
(deallocate_card): Dealloc card and all apps.
(app_ref): Rename to card_ref.
(app_unref): Rename to card_unref.
(app_unref_locked): Rename to card_unref_locked.
(card_get_serialno): New.
* scd/command.c (cmd_pkdecrypt): Actually use the looked up card and
former app object and not the standard one from the context.