Fixed navbar hides on scroll

Comes down on hover.
Currently only works for pages with a navbar and no orange masthead. In
order to have it work for all pages, we need to decide what to do with
other pages.
fix merge conflict errow
Fixed navbar hides on scroll

For all page types
Navbar improvements for more window sizes
navbar js fix for refresh
Merge pull request #248 from littleweaver/navbar-fixed

Fixed navbar to top of page