scd: Change the apptype from a string to an enum.
* scd/app-common.h (cardtype_t): New. (apptype_t): New. (struct app_ctx_s): Change type of field apptype. Add fields appversion and cardtype. Adjust all app-*.c for the new type. * scd/app.c (supported_app_list): New. (strapptype): New. (apptype_from_name): New. (app_dump_state): Use strapptype. (app_write_learn_status): Ditto. (app_getattr): Ditto. (check_conflict): Use apptype_from_name and integer comparison. * scd/app-openpgp.c: Replace app->card_version by app->appversion.
This is another patch to make backporting from 2.3 easier.