Get rid of babel-preset-es2015

.babelrc

@@ -1,5 +1,5 @@
 {
   "presets": [
-    "es2015"
+    "env"
   ]
 }

package.json

@@ -13,9 +13,9 @@
     "git graph"
   ],
   "scripts": {
-    "build": "node -r babel-register ./node_modules/.bin/webpack --progress --colors",
+    "build": "webpack --progress --colors",
     "build:watch": "yarn build --watch",
-    "release": "yarn build -p --config webpack.config.prod.js",
+    "release": "yarn build -p --config webpack.config.prod.babel.js",
     "upgrade": "yarn-upgrade-all && yarn remove d3 && yarn add d3@3.5.17",
     "lint": "standard",
     "karma": "node -r babel-register node_modules/.bin/karma start karma.conf.js --single-run",
@@ -48,7 +48,6 @@
     "babel-loader": "^7.1.2",
     "babel-plugin-lodash": "^3.3.2",
     "babel-preset-env": "^1.6.1",
-    "babel-preset-es2015": "^6.24.1",
     "codeclimate-test-reporter": "^0.5.0",
     "css-loader": "^0.28.7",
     "css-to-string-loader": "^0.1.3",