allow each request attribute rewrite

[samunders-core]

Hi. While writing sort of HTTP/FTP proxy I noticed gyokuro has no wildcard route support (as i.e. /ftp/*). I tried to abuse filters for that, only to notice those are invoked only for registered paths. So this PR installs RequestDispatcher as last Endpoint to serve as kitchen sink. Filter will finally stand its doc: "A filter applied to each incoming request before it is dispatched..." (well, all but Repository requests). BR, sam_