MDL-45041 Web Service: add_user_device doesn't store entries for different users using the same push key

This reverts commit fe43ab9b, reversing
changes made to 3e2af223.

* Removed get_config_instance_capabilities() which was from
  older reviewed vrsions of the patch
* Added note to upgrade.txt
* Fixed deprecation note
* Bump versions

Prevent the question engine from blocking return/enter key presses
from being sent to the Atto editor.

(no double newlines)

Line length issues Andrew missed off.

Add check to mod_form to prevent "reopen until pass" and "blind marking" both being on

Do not try and calculate this inside mod_assign - it's a gradebook thing only.