Make navbar fully responsive.

Changes in this pull request include:
a) making the navbar not wrap on different screen sizes (moved things around)
b) not having a large banner for the (min-width:450px) and (max-width:767px) display size. @robasaad - I did this because on an iphone in landscape mode the banner takes up a bunch of real-estate. We'll need to re-evaluate how to handle the banner. And maybe only for the actual mobile app make it bigger. Otherwise we need to keep it small.