MUMUP-1402: Collapsible Sidebar

Youtube-esque collapsible sidebar. The sidebar is shown by default, since it I don't think it would be smart to relegate the navigation for the sight to a small menu icon by default. 

Still need to add the ability to remember whether sidebar is open or closed per user. I believe that's on the uPortal side though?

### Notable tweaks:
- Mobile menu now has this black and white image of campus instead of the crest
- Quick links added to the sidebar as a concept for how this could look. I am personally a huge fan of this approach, but I know Phyllis had reservations about it.
- Marketplace icon is a star. Cog icon didn't really make sense to me.
- When sidebar is minimized, the width of the main content is col-sm-11, rather than col-sm-10. Hurray for more real estate!

I took some liberties with the style, let me know if you have any thoughts/concerns/suggestions for them.

### Screenshots:
![image](https://cloud.githubusercontent.com/assets/1919535/5480671/03ac913a-860e-11e4-92f6-13a6fb0ac515.png)

![image](https://cloud.githubusercontent.com/assets/1919535/5480683/1c93eafe-860e-11e4-8f2d-69a83bcdab8b.png)

![image](https://cloud.githubusercontent.com/assets/1919535/5480687/2cb2b1cc-860e-11e4-876b-b592e03189fe.png)

![image](https://cloud.githubusercontent.com/assets/1919535/5481366/c90f2e40-8615-11e4-9a44-7b5ac6f96e54.png)


So, this is a question of how we want to organize the code. Currently all the media queries for responsive styles are in this file. Do we want to do it that way, or mix in the media queries throughout the sections of css they pertain to? I don't really have a preference.