Update prepare() method on Action subclasses.

Fixes handle()-related strict warnings such as "Strict Standards:
Declaration of AdminPanelAction::prepare() should be compatible with
Action::prepare(array $args = Array)

Ref. #190

plugins/Event/actions/timelist.php

@@ -42,7 +42,7 @@ class TimelistAction extends Action {
      *
      * @return boolean true
      */
-    function prepare($args) {
+    function prepare(array $args = array()) {
         parent::prepare($args);
         $this->start = $this->arg('start');
         $this->duration = $this->boolean('duration', false);