[ticket/12982] Refactoring: made most JS nice.

PHPBB3-12982
[ticket/12982] Refactoring: made JS in adm nice

PHPBB3-12982
[ticket/12982] Refactoring: Cleaned up phpbb.search

PHPBB3-12982
[ticket/12982] Refactoring: Cleaned up forum_fn.js

PHPBB3-12982
[ticket/12982] Refactoring: Cleaned up crazy insert users stuff

PHPBB3-12982
[ticket/13005] Add event to display_forums() to modify category template data

While there're events to modify/add FORUM_POST/FORUM_LINK template data,
such an event is missing for FORUM_CAT forum type.

PHPBB3-13005
[ticket/13006] Add variables to the 'core.modify_quickmod_actions' event

Add $quickmod and $action variables
for the 'core.modify_quickmod_actions' event trigerring
to avoid of using global operator in corresponding extensions.

PHPBB3-13006
[ticket/12976] Correctly use plurals for attachment count in UCP navigation

PHPBB3-12976
[ticket/13052] Restore timespan parameter for check_form_key()

PHPBB3-13052
[ticket/12982] Refactoring: Killed undescriptive variables

PHPBB3-12982
Merge pull request #2939 from nickvergessen/ticket/13052

[ticket/13052] Restore timespan parameter for check_form_key()

* nickvergessen/ticket/13052:
  [ticket/13052] Restore timespan parameter for check_form_key()
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/13052] Restore timespan parameter for check_form_key()
[ticket/13042] Remove unused variables

PHPBB3-13042
[ticket/12734] Remove unnecessary error supressing

PHPBB3-12734
Merge pull request #2936 from nickvergessen/ticket/12976

[ticket/12976] Correctly use plurals for attachment count in UCP navigation

* nickvergessen/ticket/12976:
  [ticket/12976] Correctly use plurals for attachment count in UCP navigation
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/12976] Correctly use plurals for attachment count in UCP navigation

Conflicts:
	phpBB/styles/subsilver2/template/ucp_attachments.html
Merge pull request #2940 from Senky/ticket/13042

[ticket/13042] Unused var in login_box()

* Senky/ticket/13042:
  [ticket/13042] Remove unused variables
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/13042] Remove unused variables
Merge pull request #2903 from rxu/ticket/13006

[ticket/13006] Add variables to the 'core.modify_quickmod_actions' event

* rxu/ticket/13006:
  [ticket/13006] Add variables to the 'core.modify_quickmod_actions' event
Merge branch 'develop-ascraeus' into develop

* develop-ascraeus:
  [ticket/13006] Add variables to the 'core.modify_quickmod_actions' event