Merge remote-tracking branch 'github-seldaek/stability'

* github-seldaek/stability:
  Add stability docs
  Add test for Pool handling and refactor a couple things
  Add support for stabilities in lock file
  Infer stability flags for requirements that have an explicit version required of a lower stability
  Add InstalledArrayRepository to make sure the root package is not purged by the Pool because of a lower stability
  Basic handling of stability flags
  Add list of stabilities to base package
  Add minimum-stability flag on root package to filter packages by stability
  Add CompositeRepo::getRepositories
  Add package stability

src/Composer/Repository/CompositeRepository.php

@@ -36,6 +36,16 @@ class CompositeRepository implements RepositoryInterface
         $this->repositories = $repositories;
     }
 
+    /**
+     * Returns all the wrapped repositories
+     *
+     * @return array
+     */
+    public function getRepositories()
+    {
+        return $this->repositories;
+    }
+
     /**
      * {@inheritdoc}
      */

src/Composer/Repository/InstalledArrayRepository.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Repository;
+
+use Composer\Json\JsonFile;
+use Composer\Package\PackageInterface;
+use Composer\Package\Loader\ArrayLoader;
+use Composer\Package\Dumper\ArrayDumper;
+
+/**
+ * Installed array repository.
+ *
+ * This is used for serving the RootPackage inside an in-memory InstalledRepository
+ *
+ * @author Jordi Boggiano <j.boggiano@seld.be>
+ */
+class InstalledArrayRepository extends ArrayRepository implements InstalledRepositoryInterface
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function write()
+    {
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function reload()
+    {
+    }
+}