Added handling for video element, and refactored audio a bit.
Added handling for video element, and refactored audio a bit.

macmillanpublishers/HTMLBook,oreillymedia/HTMLBook,mushroomgithub/HTMLBook,gitenberg-dev/HTMLBook,wastemobile/HTMLBook,mushroomgithub/HTMLBook,macmillanpublishers/HTMLBook,gitenberg-dev/HTMLBook,wastemobile/HTMLBook,oreillymedia/HTMLBook,gitenberg-dev/HTMLBook,macmillanpublishers/HTMLBook,mushroomgithub/HTMLBook,oreillymedia/HTMLBook