Key export obj pgp

add export key function

enzevalos_iphone/Assets.xcassets/AppIcon.appiconset/Contents.json

 {
   "images" : [
     {
-      "idiom" : "iphone",
       "size" : "20x20",
+      "idiom" : "iphone",
+      "filename" : "letterbox40.png",
       "scale" : "2x"
     },
     {
-      "idiom" : "iphone",
       "size" : "20x20",
+      "idiom" : "iphone",
+      "filename" : "letterbox60.png",
       "scale" : "3x"
     },
     {
-      "idiom" : "iphone",
       "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "letterbox58.png",
       "scale" : "2x"
     },
     {
-      "idiom" : "iphone",
       "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "letterbox87.png",
       "scale" : "3x"
     },
     {
-      "idiom" : "iphone",
       "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "letterbox80.png",
       "scale" : "2x"
     },
     {
-      "idiom" : "iphone",
       "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "letterbox120-1.png",
       "scale" : "3x"
     },
     {
-      "idiom" : "iphone",
       "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "letterbox120.png",
       "scale" : "2x"
     },
     {
-      "idiom" : "iphone",
       "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "letterbox180.png",
       "scale" : "3x"
     },
     {
-      "idiom" : "ios-marketing",
       "size" : "1024x1024",
+      "idiom" : "ios-marketing",
+      "filename" : "letterbox1024.png",
       "scale" : "1x"
     }
   ],