Fix some (not all) of the issues with the header

Got rid of the bootstrap-javascript dependency (not even sure what that is), and using the actual bootstrap.min.js file instead. This seemed to fix the issue with the menu not collapsing on mobile.

Next, the title needs to be fixed - you can't click through it at the moment
Make the navbar menus be clickable on small (but not mobile-small) screens

Previously, if you resized the browser until it was almost mobile-size (except a bit bigger so that the menu was still visible, instead of collapsing into a toggle button), the menu items were not clickable because the <h2> in the center of the navbar came out on top (the title itself does not necessarily have to be long - the element itself has a constant width). Fixed by adjusting the z-index.