File events refactoring

app/Subscriber/BaseSubscriber.php

@@ -12,28 +12,4 @@ use Kanboard\Core\Base;
  */
 class BaseSubscriber extends Base
 {
-    /**
-     * Method called
-     *
-     * @access private
-     * @var array
-     */
-    private $called = array();
-
-    /**
-     * Check if a listener has been executed
-     *
-     * @access public
-     * @param  string  $key
-     * @return boolean
-     */
-    public function isExecuted($key = '')
-    {
-        if (isset($this->called[$key])) {
-            return true;
-        }
-
-        $this->called[$key] = true;
-        return false;
-    }
 }