[ticket/12540] Fix broken placeholders in language files

PHPBB3-12540
[ticket/12435] purge_notifications() fails for unused notifications

https://tracker.phpbb.com/browse/PHPBB3-12435

PHPBB3-12435
[ticket/12544] Update Plupload to 2.1.2.

PHPBB3-12544
[ticket/12435] Update the comment

PHPBB3-12435
[ticket/12533] Make <a> use all the notification item size

Changed padding CSS to the notifications' `<li>` and it's
`<a>` (immediate child) so that the `<a>` block uses all
 it's container width and height.

To compensate that, I added the padding that was in the
`<li>` to the `<a>`

PHPBB3-12533
[ticket/12533] Make <a> use all the "see all" "button"

Changed the CSS so that the `<a>` of the notifications
list for the "see all" uses all the container.

PHPBB3-12533
Merge pull request #2457 from prototech/ticket/12544

[ticket/12544] Update Plupload to 2.1.2.

* prototech/ticket/12544:
  [ticket/12544] Update Plupload to 2.1.2.
Merge pull request #2456 from Nicofuma/ticket/12435

[ticket/12435] purge_notifications() fails for unused notifications

* Nicofuma/ticket/12435:
  [ticket/12435] Update the comment
  [ticket/12435] purge_notifications() fails for unused notifications
[ticket/12547] Rename jquery.js to jquery.min.js in assets directory

phpBB uses the minified version of jQuery hence the rename.

PHPBB3-12547
Merge pull request #2454 from nickvergessen/ticket/12540

[ticket/12540] Fix broken placeholders in language files

* nickvergessen/ticket/12540:
  [ticket/12540] Fix broken placeholders in language files
Merge branch 'develop-olympus' into develop-ascraeus

* develop-olympus:
  [ticket/12540] Fix broken placeholders in language files

Conflicts:
	phpBB/language/en/common.php
	phpBB/language/en/posting.php
	phpBB/language/en/ucp.php
[ticket/12433] Use a different message when nesting of quotes is not allowed

PHPBB3-12433
[ticket/11163] Add ext/index.htm

PHPBB3-11163
Merge pull request #2464 from nickvergessen/ticket/11163

[ticket/11163] Add ext/index.htm

* nickvergessen/ticket/11163:
  [ticket/11163] Add ext/index.htm
Merge pull request #2463 from nickvergessen/ticket/12433

[ticket/12433] Use a different message when nesting of quotes is not allowed

* nickvergessen/ticket/12433:
  [ticket/12433] Use a different message when nesting of quotes is not allowed
[task/sami] Add sami/sami as a composer development dependency.

PHPBB3-12495
[task/sami] Replace phpdoctor with sami.

PHPBB3-12495
Merge branch 'task/sami' into task/sami-ascraeus

* task/sami:
  [task/sami] Replace phpdoctor with sami.
  [task/sami] Add sami/sami as a composer development dependency.

Conflicts:
	phpBB/composer.json
	phpBB/composer.lock
Merge remote-tracking branch 'brunoais/ticket/PHPBB3-12533' into develop-ascraeus

* brunoais/ticket/PHPBB3-12533:
  [ticket/12533] Make <a> use all the "see all" "button"
  [ticket/12533] Make <a> use all the notification item size
[ticket/12525] Add string argument to contact and email user language variables

In language/en/common.php:
* Introduce a new language variable 'CONTACT' => 'Contact'
* Add a string argument to lang var 'CONTACT_USER' to avoid an appended
 '{USERNAME}' in template.
* Add a string argument to lang var 'SEND_EMAIL_USER' to avoid an appended
 '{USERNAME}' in template.

Also fix typos.

PHPBB3-12525