Revert "Revert "Use es2015 loose mode after publish (#3639)"" (#3645)

This reverts commit a2d66c0fc8.

package.json

@@ -12,7 +12,6 @@
     "babel-plugin-transform-flow-strip-types": "^6.3.13",
     "babel-plugin-transform-runtime": "^6.3.13",
     "babel-preset-es2015": "^6.6.0",
-    "babel-preset-es2015-loose": "^7.0.0",
     "babel-preset-stage-0": "^6.0.0",
     "babel-runtime": "^6.0.0",
     "browserify": "^11.2.0",
@@ -51,8 +50,8 @@
   "babel": {
     "comments": false,
     "presets": [
-      "stage-0",
-      "es2015-loose"
+      ["es2015", { "loose": true }],
+      "stage-0"
     ],
     "plugins": [
       "./scripts/add-module-exports",