Preroll and End Bumper Update

Simplified opening slide, moved class and questions links to end bumper.

![screen shot 2013-10-02 at 10 46 17 am](https://f.cloud.github.com/assets/352082/1255301/0e0de534-2b83-11e3-8d39-3d40a7c31a0e.png)
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![screen shot 2013-10-02 at 10 46 01 am](https://f.cloud.github.com/assets/352082/1255302/0e0e826e-2b83-11e3-9030-da4093d2d731.png)