Improved library navigation

Librarians will be happy to hear that we've reorganized the library section a little to make it a bit easier to get around.

We've added a new tabbed navigation that provides quicker access to checkouts, categories, and a new library statistics page.

For now the new statistics page simply includes the stats that were previously on the checkouts page, but we hope to add more interesting information to this page in the future.

The checkouts page also has a new search input, meaning if you have a barcode scanner attached to your computer you can now scan a book and then mark it as returned.