[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/11358] Fixed the code according to coding guidlines.

Added proper indentation and new line after break in switch
statement.

PHPBB3-11358
[ticket/11358] Removed all trailing white spaces.

Removed all trailing white spaces with new lines.

PHPBB3-11358
Merge branch 'ticket/11358' into develop-olympus

* ticket/11358:
  [ticket/11358] Removed all trailing white spaces.
  [ticket/11358] Fixed the code according to coding guidlines.
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11358] Removed all trailing white spaces.
  [ticket/11358] Fixed the code according to coding guidlines.
Merge pull request #1184 from marc1706/ticket/11314

[ticket/11314] Improve readability and code cleanup in new JavaScript files
Merge remote-tracking branch 'hjpotter92/ticket/11225' into develop

* hjpotter92/ticket/11225:
  [ticket/11225] Deletion of unused mcp_jumpbox.html file