add playground app icons

playground/ios/playground/Images.xcassets/AppIcon.appiconset/Contents.json

 {
   "images" : [
     {
-      "idiom" : "iphone",
       "size" : "20x20",
+      "idiom" : "iphone",
+      "filename" : "Icon-40.png",
       "scale" : "2x"
     },
     {
-      "idiom" : "iphone",
       "size" : "20x20",
+      "idiom" : "iphone",
+      "filename" : "Icon-60.png",
       "scale" : "3x"
     },
     {
+      "size" : "29x29",
       "idiom" : "iphone",
+      "filename" : "Icon-29.png",
+      "scale" : "1x"
+    },
+    {
       "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-58.png",
       "scale" : "2x"
     },
     {
-      "idiom" : "iphone",
       "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-87.png",
       "scale" : "3x"
     },
     {
-      "idiom" : "iphone",
       "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "Icon-80.png",
       "scale" : "2x"
     },
     {
-      "idiom" : "iphone",
       "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "Icon-120.png",
       "scale" : "3x"
     },
     {
+      "size" : "57x57",
       "idiom" : "iphone",
-      "size" : "60x60",
+      "filename" : "Icon-57.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "57x57",
+      "idiom" : "iphone",
+      "filename" : "Icon-114.png",
       "scale" : "2x"
     },
     {
+      "size" : "60x60",
       "idiom" : "iphone",
+      "filename" : "Icon-121.png",
+      "scale" : "2x"
+    },
+    {
       "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "Icon-180.png",
       "scale" : "3x"
     }
   ],

playground/ios/playground/Images.xcassets/Contents.json

+{
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}