Add button to highlight something in an HTTP presentation.

[Mierdin]

Would be nice if we could provide a helper button that not only switches to the relevant tab (which we already have) but also highlights a portion of the iframe for an HTTP presentation that helps the user with what they're supposed to do. Like a "show me" button. This will help cut down on the need for screenshots in the lesson guide.

This will not only have to figure out a way to highlight something within the iframe, but likely also force the iframe to point to a new page.