Various updates to facilitate validating things.

app/lib/Firefly/Helper/Controllers/RecurringInterface.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace Firefly\Helper\Controllers;
+
+
+interface RecurringInterface {
+    /**
+     * Returns messages about the validation.
+     *
+     * @param array $data
+     *
+     * @return array
+     */
+    public function validate(array $data);
+}