MUMUP-1221: add loading icon to home page

Loading icon on home page now as well as marketplace. 'Add to Favorites' marketplace-light div is hidden until the layout loads. I also changed the loading gif, because I thought the other one looked a bit pixely...but open to feedback on that.
![image](https://cloud.githubusercontent.com/assets/1919535/4923377/113e0dfc-651a-11e4-90de-0b1a7a8c6843.png)