protocol :

Connect to the unix socket.
Sent request, answer response.
close unix socket connection.

Request format :
1st byte : request type
          1 - type
		  2 - USN (unique id)
		  3 - everything
		  4 - submit service (see below)
n bytes : string length : 1 byte if < 128 else the upper bit indicate that
one additional byte should be read, etc. (see codelength.h)
n bytes = string

Response format :
1st byte : number of services/devices
For each service/device :
URL :
  n bytes string length
  n bytes = Location string
ST:
  n bytes string length
  n bytes = type string
USN:
  n bytes string length
  n bytes = identifier string

request type 4 = submit service
1st byte  = 4
(k,n) bytes : length and string "ST" (service type)
(k,n) bytes : length and string "USN"
(k,n) bytes : length and string "Server"
(k,n) bytes : length and string "Location"
No answer