[ticket/13050] Allow topic/forum subscription when email/jabber is off

Currently, there's impossible to subscribe topic/forum if emails and/or jabber
is disabled. This seems to be a 3.0 leftover since 3.1 introduces new
notification system which handles this case and offers email/jabber-free
board notifications.

PHPBB3-13050
[ticket/13038] Add link to number of posts of user in viewtopic

PHPBB3-13038
Merge pull request #2931 from rxu/ticket/13050

[ticket/13050] Allow topic/forum subscription when email/jabber is off

* rxu/ticket/13050:
  [ticket/13050] Allow topic/forum subscription when email/jabber is off
Merge pull request #2926 from Senky/ticket/13038

[ticket/13038] Link user post tally to their posts

* Senky/ticket/13038:
  [ticket/13038] Add link to number of posts of user in viewtopic
[ticket/13051] Fix viewonline event, remove template data

PHPBB3-13051
[ticket/13051] Add a new core event to handle the template array

PHPBB3-13051
[ticket/13052] Remove additional parameter from check_form_key()

PHPBB3-13052
[ticket/13052] Fix appearances with multiple parameters

PHPBB3-13052
[ticket/13052] Use request class instead of $_POST and request_var()

PHPBB3-13052
Merge pull request #2935 from nickvergessen/ticket/13052

Ticket/13052 Remove additional parameter from check_form_key()

* nickvergessen/ticket/13052:
  [ticket/13052] Use request class instead of $_POST and request_var()
  [ticket/13052] Fix appearances with multiple parameters
  [ticket/13052] Remove additional parameter from check_form_key()
[ticket/13051] Rename new event core.viewonline_modify_user_row

PHPBB3-13051
[ticket/13051] Fix core event name

PHPBB3-13051
Merge pull request #2934 from VSEphpbb/ticket/13051

[ticket/13051] Fix viewonline event (recently broken) and add a new core event