Replace RevealJS static copy with Submodule

Removes the static copy+paste version (read: old) of RevealJS with a proper submodule.

The updates in the RevealJS master fixes alignment issues previously encountered where slides would show below browser window space depending on dimensions/aspect ratio/font size.

![screen shot 2013-08-17 at 2 08 16 pm](https://f.cloud.github.com/assets/352082/981662/61f04c42-0779-11e3-81ce-302e09f50dfb.png)
![screen shot 2013-08-17 at 2 08 31 pm](https://f.cloud.github.com/assets/352082/981663/6390e6f6-0779-11e3-994a-195ff2076805.png)