Change priority of attachments

Use `image` as highest prio, followed by `audio` and `video`.

This should also improve the enclosure handling.

Author: pfefferle

includes/transformer/class-post.php

@@ -311,9 +311,9 @@ protected function get_attachment() {
 		);
 
 		$media = array(
+			'image' => array(),
 			'audio' => array(),
 			'video' => array(),
-			'image' => array(),
 		);
 		$id    = $this->wp_object->ID;