Better mobile behavior

[bnorm]

Storyboards embedded on websites depend too much on keyboard input for navigation. They also allow interactivity with the storyboard content. Both of these may cause issues in situations where only a touchscreen is available (i.e., mobile devices). We probably need better behavior in both of these areas. Disable interactivity? Larger advance buttons for touch screens? This was started in #1, and it's probably the correct behavior.

[bnorm]

One thing to consider is embedded links in the text of the slides. If we still want to support them, we may need a more complex solution.