fix parsing of date parts of post url to allow 2-digit days and months

For more compatibility with the old Wordpress URLs
added nicer looking 401 error page
upgrade lib-noir and markdown-clj
clean up app-handler setup, add middleware for custom, nicer looking, error page
add nicer 404 "not found" page
fix up various file operations to return back to the proper path listing
do a proper redirect if a file cannot be served up
explicitly set content-type header for 401, 404 and 500 error pages

Apparently the local Jetty instance is a bit more forgiving of this ..?