Add "live coding slide" to T02b

As mentioned in #13 (closed), I have a minor comment on the tutorial slides.

After slide 3, could you add a slide like the last slide. That is, could you have a slide that just says something about a live demo of coding for the CircleADT. I believe that @palmes4 and @staplejw, were hoping to do a live demo of coding for this module. The slide heading just makes it explicit where we think this should happen.

Great work on the slides!