1009 handle binary error responses

closes #1009 
this function should be combined with the `not-found` function above, have it [default](https://stackoverflow.com/questions/3208347/how-to-create-default-value-for-function-argument-in-clojure) to a message of "Not found" to accommodate both of these with a single function, keeping the name `not-found` makes sense because this renders a 404.