Add upstream plugins

Signed-off-by: Adrian Nöthlich <git@promasu.tech>

wp-content/plugins/all-in-one-event-calendar/lib/notification/abstract.php

@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * Abstract class for notifications.
+ *
+ * @author     Time.ly Network Inc.
+ * @since      2.0
+ *
+ * @package    AI1EC
+ * @subpackage AI1EC.Notification
+ */
+abstract class Ai1ec_Notification extends Ai1ec_Base {
+
+    /**
+     * @var string The message to send.
+     */
+    protected $_message;
+
+    /**
+     * @var array A list of recipients.
+     */
+    protected $_recipients = array();
+
+    /**
+     * This function performs the actual sending of the message.
+     *
+     * Must be implemented in child classes.
+     *
+     * @return bool Success.
+     */
+    abstract public function send();
+
+}