 * Do a proper shut down:
   - De-register from proxy
 * Fix presence information compatible with MSN messenger (SIP mode).
 * Separate threads for reading web phone books (prevent hang while
   trying to download).
 * Multiple calls handled correctly:
   - local audio mixing
 * Implement recording/replaying of calls.
 * Fix best way of handling calling our self
 * Write manual page?
 * Create icon
 * Ring in headphone when remote ringing?!
 * Implement dis-continuous transmission of audio streams.
 * Implement evolution-data-server and LDAP PhoneBookIo
