Disabled button clarification

This is a minor pull request to differentiate disabled buttons from secondary buttons. Secondary buttons are light blue, disabled buttons are gray.

Here are two of them side-by-side:

![screen shot 2013-07-29 at 5 55 37 pm](https://f.cloud.github.com/assets/108094/875103/e02d9bd0-f899-11e2-9c28-3dadc86e496c.png)