* 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.
* 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.
* cache.c: New.
* command.c (cmd_get_passphrase): Use the cache.
(cmd_clear_passphrase): Ditto.
* gpg-agent.c: Removed unused cruft and implement the socket
based server.
(my_strusage): Take bug report address from configure.ac.
* command.c (start_command_handler): Add an argument to start as
regular server.
(start_command_handler): Enable Assuan logging.
