fix(note_validator): Restart the timeout if there is activity

Otherwise it might trigger a timeout while a bill is currently
processed.

Closes muccc#9

fnordload/note_validator.py

@@ -81,6 +81,10 @@ def read_note(self, timeout = 30, message_callback = lambda x: None):
             elif (len(poll) > 1 and poll[0] == '0xf0'):
                 self._logger.warning(str(poll))
 
+            if len(poll) > 1:
+                 # The bill acceptor is not idle. Restart the timeout
+                 t0 = time.time()
+
         with self._essp_lock:
             self._eSSP.disable()