Effect#loop now gets the time since the last run of the loop in ms. This enables

the effects to show animations that stay fluid independent of the current frame rate.

include/effect_snake.h

@@ -17,7 +17,7 @@ private:
 public:
 	SnakeEffect();
 	~SnakeEffect();
-	void loop();
+	void loop(uint16_t ms);
 	boolean valid_position(Coords c);
 	Coords update_position(Coords c, uint8_t direction);
 	boolean can_be_shown_with_clock();