Update playground with latest API

Author: cyril-sf

example/cards/ad/card.js

@@ -9,8 +9,8 @@ var card = Conductor.card({
         play: function () {
           var card = this.card;
 
-          card.promise.then(function () {
-            return card.videoCard.promise;
+          card.waitForLoad().then(function () {
+            return card.videoCard.waitForLoad();
           }).then(function () {
             card.videoCard.sandbox.videoPort.send('play');
           });
@@ -66,7 +66,7 @@ var card = Conductor.card({
     this.videoCard = this.childCards[0].card;
     this.surveyCard = this.childCards[1].card;
 
-    this.videoCard.sandbox.promise.then(function () {
+    this.videoCard.waitForLoad().then(function () {
       card.videoCard.sandbox.el.on('resize', function (dimensions) {
         card.videoCardDidResize(dimensions);
       });

example/cards/video/card.js

@@ -9,7 +9,7 @@ Conductor.card({
       events: {
         play: function () {
           var card = this.card;
-          card.promise.then(function () {
+          card.waitForLoad().then(function () {
             return card.playerDefered().promise;
           }).then(function () {
             card.player.playVideo();

example/playground/js/playground-card.js

@@ -55,7 +55,7 @@
         $(this).css('height', '');
       }).data('card', card);
 
-      card.appendTo($card.find('.card')[0]).promise.then(function() {
+      card.appendTo($card.find('.card')[0]).then(function() {
         card.render('thumbnail', {
           width: 600,
           height: 600