add --help to CLI

package.json

@@ -27,6 +27,7 @@
     "glob": "^7.1.2",
     "locate-character": "^2.0.5",
     "mkdirp": "^0.5.1",
+    "mri": "^1.1.0",
     "node-fetch": "^1.7.3",
     "relative": "^3.0.2",
     "require-relative": "^0.8.7",
@@ -52,6 +53,8 @@
     "nightmare": "^2.10.0",
     "npm-run-all": "^4.1.2",
     "rollup": "^0.53.0",
+    "rollup-plugin-json": "^2.3.0",
+    "rollup-plugin-string": "^2.0.2",
     "rollup-plugin-typescript": "^0.8.1",
     "source-map-support": "^0.5.2",
     "style-loader": "^0.19.1",