Header responsive2

@laspluviosillas @davidclarkmoore Here are the changes dave and I made for the nav bar and the side nav bar (activates when less than 800px)

A few thoughts:

1) The media query I wrote activates on a pixel based width, which might be problematic for a retina display device. I tried to change the MQ to recognize ems instead but it broke. 

2) I currently have the header and nav bar with a fixed position only when the header snaps. Not sure if we want it to be fixed all the time. 

3) We might consider killing the "Converge" text next the logo when the nav bar snaps and just have the logo. I have an image of just the logo I created and threw into our image file. I wasn't just sure how to change the image out with the media query because the image is in the HAML file, not our scss file.

So let us know what you think, James. Thanks!