title: Is there a way to use loose modules when using es2015 preset in babel 6?
body: <p>
  I tried to use following babelrcs:</p>
  
  <pre class="lang-json prettyprint-override"><code>{
    "presets": [
       ["es2015", { "transform-es2015-modules-commonjs": { "loose": true } }]
    ]
  }
  </code></pre>
  
  <p>fails with "Invalid options type for foreign"</p>
  
  <pre class="lang-json prettyprint-override"><code>{
    "presets": ["es2015"],
    "plugins": [
      ["transform-es2015-modules-commonjs", { "loose": true }]
    ]
  }
  </code></pre>
  
  <p>ignores the "loose" option</p>
  
  <pre class="lang-json prettyprint-override"><code>{
    "plugins": [
       ["transform-es2015-modules-commonjs", { "loose": true }]
    ]
  }
  </code></pre>
  
  <p>does not use the preset</p>