Places the searchbox in the header

Also:
* Removes the navigation tabs that were really from the marketing site
* Replaces nav with just a link to the website or to log in
* Moves the CSS locally, rather than fetching from the marketing site
* Moves the favicon locally
* Hides the searchbox from the header when you're on the search page
Merge pull request #39 from chargify/searchbox

Places the searchbox in the header