title: How to correctly import Gridstack using npm/webpack?
body: <p>I used npm to install gridstack library.</p>
  
  <p>I was previously using gridstack as a standard js library but I want to include it now using npm/webpack instead of directly including it by myself. 
  I don't understand what I need to include to make it working.</p>
  
  <p>I was also using the release v1.1, what are the needed dependencies ? only gridstack or you also need jquery-ui ?</p>
  
  <p>Main.js</p>
  
  <pre><code>import Gridstack from 'gridstack' //what I need to put here ?
  
  var grid = Gridstack.init();
  console.log(grid);
  </code></pre>
  
  <p>Package.json</p>
  
  <pre><code>"dependencies": {
      "@babel/polyfill": "^7.8.3",
      "@babel/runtime": "^7.8.7",
      "gridstack": "^1.1.0",
   },
  "devDependencies": {
      "@babel/core": "^7.8.4",
      "@babel/plugin-syntax-dynamic-import": "^7.8.3",
      "@babel/plugin-transform-runtime": "^7.8.3",
      "@babel/preset-env": "^7.8.4",
      "autoprefixer": "^8.6.4",
      "babel-loader": "^8.0.6",
      "cross-env": "^7.0.0",
      "webpack": "^4.41.6",
      "webpack-cli": "^3.3.11"
    },
  </code></pre>
  
  <p>For the moment I have the following error :</p>
  
  <pre><code>TypeError: gridstack__WEBPACK_IMPORTED_MODULE_7___default.a.init is not a function
  </code></pre>