title: Composer: looking for namespaced class in multiple locations
body: <p>I'm trying to figure out how to get composer to look for classes for a specific namespace under 2 directories. What I'm thinking of is this: </p>
  
  <pre><code>Default location:   /src/MyModule/myClass.php
  Override location:  /config/override/MyModule/myClass.php
  </code></pre>
  
  <p>Now, I'd like to use composer to configure the autoloader to check if a class exists under the Override location. If it does, use this class. If not, load the class from the default location. </p>
  
  <p>Is this possible using composer or would I have to implement this logic using my own autoloader? </p>