Revision 4434

redesign the client/server communication:
- no more shared memory used (allow pcscd and libpcsclite1.so to be on
  different computer and talk over a network)
- no more difference between short and extended APDU
- no more use of a /var/run/pcscd/pcscd.events/ directory. events are
  sent through the socket
- simpler command format between client and server

The side effect is that you are not able to mix an old pcscd with a new
libpcsclite1.so or the reverse. SCardEstablishContext() will fail unless
you update both sides of the communication.