Added values for new variables and manually changed the header border-bo...

I added values in the sass for $courseware-hover-color and $courseware-navigation-color. I also manually removed the blue border at the bottom of the header. The negative header image was making it look funny too. So I got rid of that as well.

![screen shot 2014-09-09 at 3 21 44 pm](https://cloud.githubusercontent.com/assets/8431091/4207466/bc55d954-3856-11e4-8615-721813a75ef8.png)
![screen shot 2014-09-09 at 3 32 46 pm](https://cloud.githubusercontent.com/assets/8431091/4207596/206f991a-3858-11e4-94a7-b9df1cb87f74.png)