Update worker code to the point that it can run.

Added plugin architecture for Worker functions, to support multiple
ripping engines.
Update worker script to use the new code.
Update Logger to output messages to console when running under the
worker script.

lib/HandBrakeCluster/Log.class.php

@@ -28,6 +28,10 @@ class HandBrakeCluster_Log {
                 array('name' => 'message', 'value' => $message, 'type' => PDO::PARAM_STR)
             )
         );
+        
+        if (HBC_File == 'worker') {
+            echo date("r") . ' ' . $message . "\n"; 
+        }
     }
 
     public function debug($message, $job_id = 0) {