title: How to get Grunt-Contrib-Copy to copy files/directories relative to given source path
body: <p>First time using this task and what I'm trying to achieve is the following: </p>
  
  <p>copy all directories/files from <code>src/js/bower_components/*</code> to <code>build/assets/js/vendor/</code></p>
  
  <p>I've tried using <code>cwd</code> property but it doesn't work at all when I use it.. I've set it to: <code>src/js/bower_components/</code></p>
  
  <p><em>From src</em></p>
  
  <pre><code>.
  ├── Gruntfile
  └── src
      └── js
          └── bower_components
              └── jquery
  </code></pre>
  
  <p><em>I currently get:</em></p>
  
  <pre><code>.
  ├── Gruntfile
  └── build
      └── assets
          └── js
              └── vendor
                  src
                  └── js
                      └── bower_components
                          └── jquery
  </code></pre>
  
  <p><em>What I'd like</em></p>
  
  <pre><code>.
  ├── Gruntfile
  └── build
      └── assets
          └── js
              └── vendor
                  └──jquery
  </code></pre>
  
  <p>Here's my current grunt task</p>
  
  <pre><code>copy: {
    main: {
      src: 'src/js/bower_components/*',
      dest: 'build/assets/js/vendor/',
      expand: true,
    }
  },
  </code></pre>
  
  <p>Thanks for any help </p>