fix broken serializer

src/js/utils/serialization/Deserializer.js

@@ -69,8 +69,9 @@
       frames.forEach(layer.addFrame.bind(layer));
       this.layers_[index] = layer;
       this.onLayerLoaded_();
-    }.bind(this)).catch(function () {
+    }.bind(this)).catch(function (error) {
       console.error('Failed to deserialize layer');
+      console.error(error);
     });
 
     return layer;

src/js/utils/serialization/Serializer.js

@@ -2,7 +2,7 @@
   var ns = $.namespace('pskl.utils.serialization');
 
   var areChunksValid = function (chunks) {
-    return chunks.every(function (chunk) {
+    return chunks.length && chunks.every(function (chunk) {
       return chunk.base64PNG;
     });
   };