add message to Dispatch exceptions (#1376)

Exceptions thrown while attempting to dispatch routes are now informing the exact value that was incorrect; url for not found routes and the method when the method was invalid.

src/Http/Middleware/DispatchRoute.php

@@ -59,9 +59,9 @@ class DispatchRoute
 
         switch ($routeInfo[0]) {
             case Dispatcher::NOT_FOUND:
-                throw new RouteNotFoundException;
+                throw new RouteNotFoundException($uri);
             case Dispatcher::METHOD_NOT_ALLOWED:
-                throw new MethodNotAllowedException;
+                throw new MethodNotAllowedException($method);
             case Dispatcher::FOUND:
                 $handler = $routeInfo[1];
                 $parameters = $routeInfo[2];