Started implementing a error 404 page
Flush the bufio writer, otherwise no content is written
Set the proper HTTP Status code in the 404 handler
Removed the console message that was printed everytime a web client tried to connect to a nonexistent item
Changed the fallback page title for items with an unknown type
Cleaned up the error 404 code and changed the content that is displayed on the error 404 page: Added the toplevel and breadcrumb navigation and changed the messaging