added new images for example

Examples/Programmatic/TextField/TextField/Assets.xcassets/ic_close_white.imageset/Contents.json

+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "ic_close_white.png",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "ic_close_white_2x.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "ic_close_white_3x.png",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}
\ No newline at end of file