added cli and generateManifest feature

[wallaroo]

hi! i've added a very simple cli to use this package as devDependency and add some npm scripts like:

  "scripts": {
    "mvn-install": "jsmvn install -c ./mvnconfig.json",
    "mvn-deploy": "jsmvn deploy spent_snapshot -s",

    "prepare": "npm run build",
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject"
  }

[coveralls]

Coverage increased (+0.1%) to 98.16% when pulling 55b967a on wallaroo:master into 28c6979 on finn-no:master.