Fader

	IEnumerator FadeMessage (MessageDisplay thisDisplay, Message thisMessage) {
		float fadeDelay = thisDisplay.fadeDelay;
		float fadeSpeed = thisDisplay.fadeSpeed;
		yield return new WaitForSeconds (fadeDelay);
		float fadeTimer = 0.0f;
		while (fadeTimer < fadeSpeed) {
			thisMessage.color.a = Mathf.Lerp(0, 1, (fadeSpeed - fadeTimer) / fadeSpeed);
			fadeTimer += Time.deltaTime;
			UpdateDisplay (thisDisplay);
			yield return null;
		}
		if (thisMessage != null)
			DeleteThisMessage (thisDisplay, thisMessage);
	}