Some basic styles

Added a main page. Now it no longer goes to popular bills right away
Added style for the main page and a nav bar on top for all pages.
Styling from bootstrap

Known "features":
Carousel doesn't work till you click on it for the first time
Need to change the sign-in options on top once the user has signed in (currently always gives the sing-in boxes)
Need to put some more meaningful images and text in the carousel