before/after interceptor

[jknack]

next version will have a pre/post interceptor, like:

{
   before("*", (req, rsp) -> {
     ...
   });

  after("*", (req, rsp) -> {
     ...
   });
}

please note these two operations will be implemented as Route.Filter, so they will be syntax sugar for:

{
    use("*", (req, rsp, chain) -> {
      before(req, rsp);
      chain.next(req, rsp);
      after(req, rsp);
    });
}