CC-1672 Implement scheduler class in PHP

Part 1 of this implementation
This implementation keeps the playlists separate from the scheduler.
The scheduler keeps it's own copy of the list of things to play.

Support for adding single audio files to the scheduler is mostly implemented.
Adding playlists is not supported yet.

Added Scheduler.php class.
Added unit tests for Scheduler.

Updated install & upgrade file with new table structure.

Removed a lot of old defunct unit test stuff from storageServer /var/tests dir.

src/modules/storageServer/var/StoredFile.php

@@ -1003,14 +1003,12 @@ class StoredFile {
 
 
     /**
-     * Get metadata as XML string
+     * Get metadata as array, indexed by the column names in the database.
      *
-     * @return XML string
-     * @see MetaData
+     * @return array
      */
     public function getMetadata()
     {
-        //return $this->md->getMetadata();
         return $this->md;
     }