Convert recipe examples to includes

Makes it much easier to test things - no copying'n'pasting just run the
examples straight from the dir (after wiring stuff up)

docs/examples/robot_1.py

@@ -0,0 +1,10 @@
+from gpiozero import Robot
+from time import sleep
+
+robot = Robot(left=(4, 14), right=(17, 18))
+
+for i in range(4):
+    robot.forward()
+    sleep(10)
+    robot.right()
+    sleep(1)