Added try...except to be more safe after pprzlink api changes. (#2548)

* Updated pprzlink library to the latest version

* Added try...except to crazyradio2ivy.py to be safer after pprzlink API changes. paparazzi/pprzlink#117

* Updated request messages with the new pprzlink API

* Added a #noqa comment so linters won't remove the seemingly unused import.

* Updated the guided_mode_example.py to have a wait timeout.

sw/ground_segment/python/bitcraze/crazyradio2ivy.py

@@ -98,7 +98,12 @@ class RadioBridge:
                         print("Got message {} from {}".format(msg.name, sender_id))
                     # Forward message to Ivy bus
                     if self.is_connected:
-                        self._ivy.send(msg, sender_id=sender_id)
+                        try:
+                            self._ivy.send(msg, sender_id=sender_id)
+                        except RuntimeError as e:
+                            print("Runtime error {}".format(e))
+                        except ValueError as e:
+                            print("Invalid message error {}".format(e))
 
     def _link_quality_cb(self, quality):
         pass

sw/ground_segment/python/guided_mode_example.py

@@ -161,17 +161,26 @@ class IvyRequester(object):
             self._interface = None
 
     def get_aircrafts(self):
+        wait_step = 0.1
+        timeout = 30 / wait_step  # 30 seconds
+        new_answer = False
 
         def aircrafts_cb(ac_id, msg):
+            global new_answer
             self.ac_list = [int(a) for a in msg['ac_list'].split(',') if a]
             print("aircrafts: {}".format(self.ac_list))
+            new_answer = True
 
-        self._interface.subscribe(aircrafts_cb, "(.*AIRCRAFTS .*)")
-        sender = 'get_aircrafts'
-        request_id = '42_1' # fake request id, should be PID_index
-        self._interface.send("{} {} AIRCRAFTS_REQ".format(sender, request_id))
+        self._interface.send_request('ground', "AIRCRAFTS", aircrafts_cb)
         # hack: sleep briefly to wait for answer
-        sleep(0.1)
+        while not new_answer and timeout > 0:
+            sleep(wait_step)
+            timeout -= 1
+
+        if not new_answer:
+            print("WARNING: Getting the list of aircraft timed out. The results might be outdated.")
+            # Didn't raise an exception or return None in order to not break the API
+
         return self.ac_list