Allow on-demand loading of controller with just `controllerUrl` parameter

[marcoslin]

Currently, both controller and controllerUrl is needed when using angularAMD.route:

$routeProvider.when(
    "/home",
    angularAMD.route({
        templateUrl: 'views/home.html',
        controller: 'HomeController',
        controllerUrl: 'scripts/controller.js'
    })
);

Ideally, .route method should allow passing of just controllerUrl parameter:

$routeProvider.when(
    "/home",
    angularAMD.route({
        templateUrl: 'views/home.html',
        controllerUrl: 'scripts/controller.js'
    })
);

Where scripts/controller.js would simply return a function:

define(['app'], function (app) {
    return ["$scope", function ($scope) {
        $scope.message = "Message from View1Ctrl";
    }];
});