[ticket/11314] Cleanup core.js coding

function errorHandler() was used in returnHandler() before it was defined.
The unused variable alert has been removed from errorHandler(). Overuse of
the var keyword for the variable sign has been removed and the if
statement has been simplified. The definition of the variable i has been
moved outside of the for loop definition. The var keyword shouldn't be
used inside the definition of the for loop.

PHPBB3-11314
[ticket/11314] Add missing semi-colons

Omitting the semi-colon is not legal behavior for JavaScript.

PHPBB3-11314
[ticket/11314] Use return variable instead of overusing the return keyword

Use a return variable and modify it to our needs.

PHPBB3-11314
[ticket/11314] Add missing "use strict" to timezone.js files

PHPBB3-11314
[ticket/11314] Fix whitespace issues

PHPBB3-11314
[ticket/11314] Add missing radix parameters

PHPBB3-11314
Merge branch 'develop' of https://github.com/phpbb/phpbb3 into ticket/11314
[ticket/11314] Fix issues mentioned in jshint report

Additionally, the editor.js files are now the same file in both
subsilver2, prosilver, and the acp.

PHPBB3-11314
[ticket/11314] Fix JSHint issues in adm editor.js

This time without changing the behavior.

PHPBB3-11314
[ticket/11314] Modify files to comply with coding standards

PHPBB3-11314
Merge branch 'develop' of https://github.com/phpbb/phpbb3 into ticket/11314

Conflicts:
	phpBB/styles/prosilver/template/timezone.js
[ticket/11225] Deletion of unused mcp_jumpbox.html file

The file/template is no longer used(as mentioned in it).

PHPBB3-11225
[ticket/11116] Made ACP "extension not available" error message E_USER_WARNING

The error message generated when an administrator tries to enable an
incompatible extension used to be displayed in the green of the default
E_USER_NOTICE. Changed it to E_USER_WARNING to make it appear in red, as
requested in the ticket.

PHPBB3-11116
[ticket/11492] Add functional test for empty teampage

PHPBB3-11492
[ticket/11492] Add tests for removing/adding users

PHPBB3-11492
[ticket/11492] Do not add the user again

PHPBB3-11492
[ticket/11492] Split into mutliple tests

PHPBB3-11492
[ticket/11492] Fix issues with log object

PHPBB3-11492
[ticket/11492] Fix the test once more

PHPBB3-11492
[ticket/11492] Initialize $user_ids and $group_users arrays

Also avoid unneccessary calls to permissions when user_ids is empty

PHPBB3-11492