dul 6.x-1.4

Differences with the previous 6.x-1.3 version:

• #452188: The code changes the language for all the users in once.
• #452146: The language is still reset for all the users.
• The change own language is now checked for the account being edited, not the user currently editing the account; the difference is clear when a user with the permission to administer users edits another user's account.