Updates to make navigation functional

I learned how to refactor code by adding it to a function. I also
learned how to grab the GET subject and search for a selected ID which
added a special "selected" class to the nav. Lastly, I added a large
function for the navigation. This showed me how to refactor, returning
everything into a variable called "output" and how to add ags for
variables. Need to remember that the args can be anything but get
converted to the local scope