title: Assetic: Cannot find module 'less'
body: <p>The problem:</p>
  
  <ul>
  <li>I am using laravel 4 + basset for asset management (OSX).</li>
  <li>i have added the twitter bootstrap to my composer as a dependency.</li>
  <li><p>I want to compile the less files into a collection:</p>
  
  <pre><code>Basset::collection('TwitterBootstrap', function($collection)
  {
      // Collection definition.
      $collection-&gt;add('../vendor/twbs/bootstrap/less/bootstrap.less');
  })-&gt;apply('Less');
  </code></pre></li>
  <li><p>I then try to build the collection:</p>
  
  <pre><code>php artisan basset:build TwitterBootstrap
  </code></pre></li>
  <li><p>Which throws the error:</p>
  
  <pre><code>[Assetic\Exception\FilterException]
    An error occurred while running:
    '/usr/local/bin/node' '/private/var/folders/f4/xjby77695pbcgfdjfclfdqd40000gn/T/assetic_less5y7dnh'
  
    Error Output:
  
    module.js:340
        throw err;
              ^
    Error: Cannot find module 'less'
        at Function.Module._resolveFilename (module.js:338:15)
        at Function.Module._load (module.js:280:25)
        at Module.require (module.js:364:17)
        at require (module.js:380:17)
        at Object.&lt;anonymous&gt; (/private/var/folders/f4/xjby77695pbcgfdjfclfdqd40000gn/T/assetic_less5y7dnh:1:74)
        at Module._compile (module.js:456:26)
        at Object.Module._extensions..js (module.js:474:10)
        at Module.load (module.js:356:32)
        at Function.Module._load (module.js:312:12)
        at Function.Module.runMain (module.js:497:10)
  </code></pre></li>
  </ul>
  
  <p>I have installed less globally - im unsure why this is throwing errors/what to fix (my path? a node config? an assetic config?)</p>