V4 updates (#210)

* update pxt.json files

* Fix button event enums

fixes https://github.com/microsoft/pxt-calliope/issues/206

* Fix Safari CSS Rule for iOS app

fixes https://github.com/microsoft/pxt-calliope/issues/205

* aprove preffered repos

should fix https://github.com/microsoft/pxt-calliope/issues/167

libs/servo/pxt.json

@@ -1,14 +1,16 @@
 {
-    "additionalFilePath": "../../node_modules/pxt-common-packages/libs/servo",
+    "name": "servo",
+    "description": "A micro-servo library",
+    "dependencies": {
+        "core": "file:../core"
+    },
     "files": [
         "README.md",
         "servo.ts",
         "ns.ts",
         "targetoverrides.ts"
     ],
-    "icon": "./static/packages/servo/icon.png",
     "public": true,
-    "dependencies": {
-        "core": "file:../core"
-    }
-}
+    "additionalFilePath": "../../node_modules/pxt-common-packages/libs/servo",
+    "icon": "./static/packages/servo/icon.png"
+}