Merge branch 'MDL-52489_master' of git://github.com/markn86/moodle

diff --cc mod/assign/locallib.php
Simple merge

diff --cc mod/assign/submission/file/locallib.php
Simple merge

diff --cc mod/assign/upgrade.txt
index 7cadc8d,4047336..e6c4652
--- 1/mod/assign/upgrade.txt
--- 2/mod/assign/upgrade.txt
+++ b/mod/assign/upgrade.txt
@@@ -1,8 -1,9 +1,10 @@@
  This files describes API changes in the assign code.
  
  === 3.1 ===
 -
 +* The feedback plugins now need to implement the is_feedback_modified() method. The default is to return true
 +  for backwards compatibiltiy.
+ * When downloading all submissions as a zip each students' files are in a separate folder, are no longer renamed
+   and the folder structure is kept intact.
  
  === 3.0 ===
  * assign_submission_status renderable now requires $usergroups in its constructor