Now UnfilteredApp is Pass aware

* Now we can use Pass on #> Intents. s/orElse/onPass/

* Added ThrowableOps with method stackTrace, get easily the
exception stack trace in a String

* =>?? expects a Directive with Future[(String, Map[String,Any])]
=>?? passes now the template to render.

Added support to pass the template to render when injectin =>?? values.

Now using Error:Result as Pass.
This needs to be changed adding a Pass:Result.