MDL-40709 skydrive: filter files by accepted types

This means images will only be shown in the image picker, videos
in the video picker - etc.

repository/skydrive/lib.php

@@ -96,7 +96,11 @@ public function get_listing($path='', $page = '') {
         $ret['dynload'] = true;
         $ret['nosearch'] = true;
         $ret['manage'] = 'https://skydrive.live.com/';
-        $ret['list'] = $this->skydrive->get_file_list($path);
+
+        $fileslist = $this->skydrive->get_file_list($path);
+        // Filter list for accepted types. Hopefully this will be done by core some day.
+        $fileslist = array_filter($fileslist, array($this, 'filter'));
+        $ret['list'] = $fileslist;
 
         // Generate path bar, always start with the plugin name.
         $ret['path']   = array();