[ticket/11672] Removed unnecessary text from alerts.

Messages like "Return to forum last visited" are entirely unnecessary
when using AJAX to delete a post, so this commit removes them.

PHPBB3-11672
[ticket/11672] Replace sprintf() usage with $user->lang().

PHPBB3-11672
[ticket/11672] Remove some messages that were missed in mcp_queue.php.

PHPBB3-11672
[ticket/11672] Clean up the logic in mcp_queue.php.

PHPBB3-11672
[ticket/11672] Remove the messages for lock/unlock/change topic type.

PHPBB3-11672
[ticket/11672] The json response call exits so the else is not necessary.

PHPBB3-11672
[ticket/11672] Remove duplicate $request global.

PHPBB3-11672
[ticket/11984] Prevent AJAX background animation flicker in ACP

PHPBB3-11984
[ticket/11984] Prevent AJAX background animation flicker in prosilver

PHPBB3-11984
[ticket/11984] Fix stray </ul> and active tab hover in ACP

PHPBB3-11984
[ticket/11984] Hide <dfn> for invalid extensions

PHPBB3-11984
[ticket/11984] Do not resize textarea on touch devices

PHPBB3-11984
[ticket/11979] Fix errors in dropdown

PHPBB3-11979
[ticket/11842] Add migration file for updating avatar type in database

PHPBB3-11842
[ticket/11842] Use only new avatar type in user_delete function

PHPBB3-11842
[ticket/12026] Correct path for template files

Correct path for template files in MCP and UCP modules, which are added
via extenstions

PHPBB3-12026
[ticket/12026] Remove phpbb root path

PHPBB3-12026
[ticket/11672] Move the reapply_sid() call before meta_refresh() is called.

The $redirect assignment is not necessary because the variable  has already been
set near the start of the functions. The redirect value will also never default
to index.php because a default value has already been provided when $redirect
is initially assigned and passed to the template as a hidden field.

PHPBB3-11672
[ticket/11484] Display login box for users following email notification link.

The link used for the latest post now uses view=unread so redirecting the user
using the value for the e parameter is no longer necessary.

PHPBB3-11484
[ticket/11959] Trim the list of users from post notifications.

PHPBB3-11959