Add option --card-timeout.

Add a new attribyte to app-openpgp.c
Fix two portability bugs.
Have gpg-connect-agent autostart gpg-agent on W32.

scd/scdaemon.h

@@ -61,6 +61,7 @@ struct
                           cards. */
   strlist_t disabled_applications;  /* Card applications we do not
                                        want to use. */
+  unsigned long card_timeout; /* Disconnect after N seconds of inactivity.  */
 } opt;