title: Retaining output colors when shelling out to node
body: <p>I have a little Grunt task that shells out via node and runs "composer install".</p>
  
  <pre><code>var done = this.async();
  
  var exec = require('child_process').exec;
  var composer = exec(
      'php bin/composer.phar install',
      function(error, stdout, stderr) {
          done(error===null);
      }
  );
  
  composer.stdout.on(
      'data',
      grunt.log.write
  );
  </code></pre>
  
  <p>As you can see, I'm outputting the stdout of this child process to grunt.log. All output is showing up nice and well as expected, except that the output is all in my default console color. If I run "composer install" directly I get highlighting that improves readability.</p>
  
  <p>Since I'm new to node, Grunt and shelling out in general, I'm unsure about in which part of the system the coloring gets lost, or even how to debug this efficiently.</p>