Placeholders for Bluray rips

Added placeholder Source/Worker plugins for ripping Bluray items.
Added placeholder iterator filter to accept only Bluray sources while
iterating directory contents.

lib/RippingCluster/Worker/Plugin/Bluray.class.php

@@ -0,0 +1,53 @@
+<?php
+
+class RippingCluster_Worker_Bluray extends RippingCluster_PluginBase implements RippingCluster_Worker_IPlugin {
+    
+    const PLUGIN_NAME = 'Bluray';
+    
+    private $output;
+    
+    private $job;
+    
+    private $rip_options;
+    
+    private function __construct(GearmanJob $gearman_job) {
+        $this->output = '';
+        
+        $this->gearman_job = $gearman_job;
+        
+        $this->rip_options = unserialize($this->gearman_job->workload());
+
+        if ( ! $this->rip_options['id']) {
+            throw new RippingCluster_Exception_LogicException("Job ID must not be zero/null");
+        }
+        $this->job = RippingCluster_Job::fromId($this->rip_options['id']);
+    }
+    
+    /**
+     * Returns the list of functions (and names) implemented by this plugin for registration with Gearman
+     * 
+     * @return array(string => callback)
+     */
+    public static function workerFunctions() {
+        return array(
+            'bluray_rip' => array(__CLASS__, 'rip'),
+        );
+    }
+    
+    /**
+     * Creates an instance of the Worker plugin, and uses it to execute a single job
+     *
+     * @param GearmanJob $job Gearman Job object, describing the work to be done
+     */
+    public static function rip(GearmanJob $job) {
+        $rip = new self($job);
+        $rip->execute();
+    }
+        
+    private function execute() {
+        // TODO
+    }
+    
+}
+
+?>