core (xmpp): implemented human friendly __unicode__ for client

sat/core/xmpp.py

@@ -69,6 +69,12 @@ class SatXMPPEntity(object):
         self.actions = {}  # used to keep track of actions for retrieval (key = action_id)
         self.encryption = encryption.EncryptionHandler(self)
 
+    def __unicode__(self):
+        return u"Client instance for profile {profile}".format(profile=self.profile)
+
+    def __str__(self):
+        return self.__unicode__.encode('utf-8')
+
     ## initialisation ##
 
     @defer.inlineCallbacks