showencoders.py: read encoders once to reset them

controller/python/showencoders.py

@@ -6,6 +6,9 @@ from controller import Controller
 
 c = Controller()
 
+# Reset encoders
+c.get_encoder_ticks()
+
 left, right = 0, 0
 while True:
     dl, dr = c.get_encoder_ticks()