[ticket/12576] Remove cron from common.php

PHPBB3-12576
[ticket/12576] Retrieve the cron_manager in cron.php if needed

PHPBB3-12576
Merge pull request #2484 from Nicofuma/ticket/12576

[ticket/12576] Remove cron from common.php

* Nicofuma/ticket/12576:
  [ticket/12576] Retrieve the cron_manager in cron.php if needed
  [ticket/12576] Remove cron from common.php
Merge pull request #2465 from prototech/ticket/12549

[ticket/12549] Hide topic/forum list <dfn> tags in RTL languages.

* prototech/ticket/12549:
  [ticket/12549] Hide topic/forum list <dfn> tags in RTL languages.
Merge pull request #2466 from prototech/ticket/12550

[ticket/12550] Prevent last post column from jumping to second line in RTL.

* prototech/ticket/12550:
  [ticket/12550] Prevent last post column from jumping to second line in RTL.
Merge pull request #2467 from prototech/ticket/12551

[ticket/12551] Float breadcrumbs to the right in RTL languages.

* prototech/ticket/12551:
  [ticket/12551] Float breadcrumbs to the right in RTL languages.