title: Composer require-dev autoload from package not added to project's autoload
body: <p>I have made a composer package with the following settings in the composer.json file:</p>
  
  <pre><code>"autoload": {
      "psr-4": {
          "MyVendor\\MyPackage\\": "src/"
      }
  },
  "autoload-dev": {
      "psr-4": {
          "Test\\Unit\\MyProject\\MyPackage\\": "test/unit"
      }
  },
  </code></pre>
  
  <p>If I run composer install, enforcing dev param, and I get the following "autoload_psr4.php" file:</p>
  
  <pre><code>&lt;?php
  
  // autoload_psr4.php @generated by Composer
  
  $vendorDir = dirname(dirname(__FILE__));
  $baseDir = dirname($vendorDir);
  
  return array(
      'Test\\Unit\\MyVendor\\MyPackage\\' =&gt; array($baseDir . '/test/unit'),
      'MyVendor\\MyPackage\\' =&gt; array($baseDir . '/src'),
  );
  </code></pre>
  
  <p>So basically, everything is working fine here. Then, I add the package to a Satis server.</p>
  
  <p>In my project's composer.json file, I add the following line:</p>
  
  <pre><code>"require": {
      "myvendor/mypackage": "1.0.*@dev",
      "symfony/http-foundation": "2.5.*",
      "symfony/http-kernel": "2.5.*"
  }
  </code></pre>
  
  <p>Once again, I run composer install, enforcing dev param, in my project. The package gets installed in "vendor/myvendor/mypackage folder" and I know the DEV version is installed because the "test" folder is there (test folder is excluded (archive exclude) on stable releases).</p>
  
  <p>But, the following line is missing from the "autoload_psr4.php" file</p>
  
  <pre><code>'Test\\Unit\\MyVendor\\MyPackage\\' =&gt; array($baseDir . '/test/unit'),
  </code></pre>
  
  <p>Here is the composer install command I used:</p>
  
  <pre><code>composer install --dev -d /var/www/myproject
  </code></pre>
  
  <p>Basically, I am wondering why my package's dev namespace is not added to the autoloader. Can someone explain?</p>