add source information to route

[jknack]

A new Route.Source interface will be available with 2 methos: line and declaringClass

For example if the next route is defined at line 25, this route prints 25:

{
   get("/", req -> {
     return req.route().line();
   });
}

Goal of Source interface is to help and provide useful information for debugging purpose.

The default error handler will be modified to include this information.

See #177