Tidied plugin architecture.

Moved common default init/name methods to a base class, common to all
plugin types.
Added phpdoc comments to various plugin methods.
Updated HandBrake plugins to reflect core changes.

lib/RippingCluster/Worker/IPlugin.class.php

@@ -2,8 +2,18 @@
 
 interface RippingCluster_Worker_IPlugin extends RippingCluster_IPlugin {
     
+    /**
+     * Returns the list of functions (and names) implemented by this plugin for registration with Gearman
+     * 
+     * @return array(string => callback)
+     */
     public static function workerFunctions();
 
+    /**
+     * 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);
 
 }