Clojurians Log v2

The Ring resource handler has a bug. If the mime type cannot be found, it sets the content type to the empty string. This makes it difficult to use wrap-content-type on the result since it sees an existing header. I think the resource handler should only set the content type if a mime type has been found. Also it'd be nice if it took in a :mime-types parameter like wrap-content-type does so the extra middleware isn't needed

I can send in a PR