title: Is it possible to define a color resource as a darker/lighter version of another color resource
body: <p>Want to achieve something like this</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;resources&gt;
      &lt;color name="titleTextColor"&gt;#3D78CC&lt;/color&gt;
      &lt;color name="titleBackgroundColor"&gt;lighter version of titleTextColor&lt;/color&gt;
  &lt;/resources&gt;
  </code></pre>
  
  <p>so that just changing the title text color changes the background color, and I dont have to set it separately</p>