title: How to specify multiple source-maps in uglify grunt task?
body: <p>I am using <code>grunt-contrib-uglify</code> plugin in my <code>grunt 0.4</code>.</p>
  
  <p>I have the following task:</p>
  
  <pre><code>uglify: {
    dist: {
      options: {
        sourceMap: 'dist/sm/sm.js'
      },
      files: grunt.file.expandMapping(['*.js'], 'dist/js', {
        cwd: 'dist/js'
      })
    }
  },
  </code></pre>
  
  <p>As you can see, uglify is configured to compress multiple files, and there is only one source-map specified. (I am not able to figure out a way to specify multiple sourcemap outputs). </p>
  
  <p>Also, uglify is overwriting the soucemap after compressing each js file.</p>
  
  <p>How do I configure this plugin to output the complete source-maps for all my js files?</p>