title: Vueify: 'import' and 'export' may appear only with 'sourceType: module'
body: <p>I am using Vue.
  This is how I'm building in my gulpfile:</p>
  
  <pre><code>browserify('./main.js')
  .transform(vueify)
  .bundle()
  .pipe( fs.createWriteStream('./build/bundle.js') );
  </code></pre>
  
  <p>The problem is vueify doesn't handle the es6 exports in my .js files. It only works in .vue components.  It works with <code>module.exports</code>, but I'd like to take advantage of es6 code in my .js files. </p>
  
  <p>When <code>bundle()</code> is called, I currently get the error:</p>
  
  <p><code>'import' and 'export' may appear only with 'sourceType: module'</code></p>
  
  <p>Is there any way to modify the gulpfile to handle js files using es6 that my .vue components are importing?</p>