Compiles CoffeeScript into Javascript.
@link http://coffeescript.org/ @author Kris Wallsmith <kris.wallsmith@gmail.com>
Expanded class hierarchy of CoffeeScriptFilter
class CoffeeScriptFilter extends BaseNodeFilter {
  private $coffeeBin;
  private $nodeBin;
  // coffee options
  private $bare;
  public function __construct($coffeeBin = '/usr/bin/coffee', $nodeBin = null) {
    $this->coffeeBin = $coffeeBin;
    $this->nodeBin = $nodeBin;
  }
  public function setBare($bare) {
    $this->bare = $bare;
  }
  public function filterLoad(AssetInterface $asset) {
    $input = tempnam(sys_get_temp_dir(), 'assetic_coffeescript');
    file_put_contents($input, $asset
      ->getContent());
    $pb = $this
      ->createProcessBuilder($this->nodeBin ? array(
      $this->nodeBin,
      $this->coffeeBin,
    ) : array(
      $this->coffeeBin,
    ));
    $pb
      ->add('-cp');
    if ($this->bare) {
      $pb
        ->add('--bare');
    }
    $pb
      ->add($input);
    $proc = $pb
      ->getProcess();
    $code = $proc
      ->run();
    unlink($input);
    if (0 !== $code) {
      throw FilterException::fromProcess($proc)
        ->setInput($asset
        ->getContent());
    }
    $asset
      ->setContent($proc
      ->getOutput());
  }
  public function filterDump(AssetInterface $asset) {
  }
}