Massive refactor of the analyzer branch and sync it back up with the

cloud storage branch (for the last time)

* Backported all the bugfixes from cc-5709-airtime-analyzer-cloud-storage
* Backported missing FileStorageBackend.php
* Fixed CC-6001: Track titles and artist names with slashes break audio preview
* Refactored all the MediaController code, pulling out the logic into MediaService
* Fixed an API key leak to guests in the Media API
* Made this branch work without cloud_storage.conf (defaults to file storage)
* Made ApiController's getMediaAction use the MediaService code

airtime_mvc/application/cloud_storage/FileStorageBackend.php

@@ -0,0 +1,41 @@
+<?php
+
+class FileStorageBackend extends StorageBackend
+{
+    //Stub class
+    public function FileStorageBackend()
+    {
+    }
+
+    public function getAbsoluteFilePath($resourceId)
+    {
+        //TODO
+        return $resourceId;
+    }
+
+    public function getSignedURL($resourceId)
+    {
+        return "";
+    }
+
+    public function getFileSize($resourceId)
+    {
+        //TODO
+        return filesize($resourceId);
+    }
+
+    public function deletePhysicalFile($resourceId)
+    {
+        //TODO
+    }
+
+    public function deleteAllCloudFileObjects()
+    {
+        return "";
+    }
+
+    public function getFilePrefix()
+    {
+        return "";
+    }
+}