Add minimist for gulp argument parsing

Author: eKoopmans

package-lock.json

@@ -37,6 +37,7 @@
     "babel-plugin-transform-object-assign": "^6.22.0",
     "babel-preset-env": "^1.7.0",
     "gulp": "^4.0.0",
+    "minimist": "^1.2.0",
     "rimraf": "^2.6.2",
     "rollup": "^0.51.8",
     "rollup-plugin-babel": "^3.0.2",