Fixed examples, added changeNickname and changeThreadEmoji, changed changeGroupTitle back to changeThreadTitle

I also removed the parameter `set_default_events` from __init__, since
it's not really necessary
Also added testing of examples and simple testing of listen functions

examples/echobot.py

@@ -4,15 +4,15 @@ from fbchat import log, Client
 
 # Subclass fbchat.Client and override required methods
 class EchoBot(Client):
-    def onMessage(self, mid, author_id, message, thread_id, thread_type, ts, metadata, msg):
+    def onMessage(self, author_id, message, thread_id, thread_type, **kwargs):
         self.markAsDelivered(author_id, thread_id)
         self.markAsRead(author_id)
 
-        log.info("Message from {} in {} ({}): {}".format(author_id, thread_id, thread_type.name, message)))
+        log.info("Message from {} in {} ({}): {}".format(author_id, thread_id, thread_type.name, message))
 
         # If you're not the author, echo
         if author_id != self.uid:
             self.sendMessage(message, thread_id=thread_id, thread_type=thread_type)
 
 client = EchoBot("<email>", "<password>")
-client.listen()
+client.listen()