Use babel-preset-es2015 in npm build

Author: dfcook

package-lock.json

@@ -6,7 +6,7 @@
   "scripts": {
     "test": "jest --coverage",
     "coveralls": "cat ./coverage/lcov.info | ./node_modules/.bin/coveralls",
-    "version": "babel src --out-dir npm"
+    "version": "babel --presets=es2015 src --out-dir npm"
   },
   "author": "Daniel Cook",
   "license": "MIT",
@@ -19,6 +19,7 @@
     "babel-plugin-transform-object-rest-spread": "^6.26.0",
     "babel-plugin-transform-runtime": "^6.23.0",
     "babel-preset-env": "^1.6.1",
+    "babel-preset-es2015": "^6.24.1",
     "coveralls": "^3.0.0",
     "jest": "^22.4.2",
     "jest-in-case": "^1.0.2",