* query.c (agent_askpin): Use the callback to check for a correct
PIN. Removed the start_err_text argument becuase it is not
anymore needed; changed callers.
* findkey.c (unprotect): Replace our own check loop by a callback.
(try_unprotect_cb): New.
* genkey.c (reenter_compare_cb): New.
(agent_genkey): Use this callback here. Fixed setting of the pi2
variable and a segv in case of an empty PIN.
* divert-scd.c (getpin_cb): Removed some unused stuff and
explained what we still have to change.
* call-scd.c: Seirialized all scdaeom access when using Pth.
* cache.c: Made the cache Pth-thread-safe.
(agent_unlock_cache_entry): New.
* findkey.c (unprotect): Unlock the returned cache value.
* command.c (cmd_get_passphrase): Ditto.
* gpg-agent.c (main): Register pth_read/write with Assuan.
* gpgsm.c: New command --learn-card
* call-agent.c (learn_cb,gpgsm_agent_learn): New.
* gpgsm.c (main): Print error messages for non-implemented commands.
agent/
* learncard.c: New.
* divert-scd.c (ask_for_card): The serial number is binary so
convert it to hex here.
* findkey.c (agent_write_private_key): New.
* genkey.c (store_key): And use it here.
scd/
* pkdecrypt.c (agent_pkdecrypt): Changed the way the diversion is done.
* divert-scd.c (divert_pkdecrypt): Changed interface and
implemented it.
* protect.c (agent_private_key_type): New.
* agent.h: Add PRIVATE_KEY_ enums.
* findkey.c (agent_key_from_file): Use it to decide whether we
have to unprotect a key.
(unprotect): Cache the passphrase.
* findkey.c (agent_key_from_file,agent_key_available): The key
files do now require a ".key" suffix to make a script's life
easier.
* genkey.c (store_key): Ditto.
