[ticket/11145] Wrong error thrown when uploading a bigger image.

When attaching an image to a post with a size larger than maximum defined in
php.ini, 'ATTACHED_IMAGE_NOT_IMAGE' error is thrown. $file->is_image() is
returning false value when image size is too large. Therefore, moved
not image test down after image size test.

PHPBB3-11145
[ticket/11549] Do not set extension dir path for style in adm/index.php

As we don't want style files in adm/adm/style/ we should not prepend the adm/
by setting it. Note, we did that correctly in adm/swatch.php.

PHPBB3-11549
[ticket/11549] Add functional test for ACP Extension Module with Template

PHPBB3-11549
Merge remote-tracking branch 'nickvergessen/ticket/11549' into develop

* nickvergessen/ticket/11549:
  [ticket/11549] Add functional test for ACP Extension Module with Template
  [ticket/11549] Do not set extension dir path for style in adm/index.php
[ticket/10840] Add check_form_key to acp_groups.php

PHPBB3-10840
[ticket/11122] Remove Oleg and igorw from active authors

PHPBB3-11122
[ticket/11122] Add dhruv to active authors

PHPBB3-11122
Merge remote-tracking branch 'nickvergessen/ticket/11122-2' into develop-olympus

* nickvergessen/ticket/11122-2:
  [ticket/11122] Add dhruv to active authors
  [ticket/11122] Remove Oleg and igorw from active authors
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11122] Add dhruv to active authors
  [ticket/11122] Remove Oleg and igorw from active authors
Merge remote-tracking branch 'nickvergessen/ticket/10840' into develop-olympus

* nickvergessen/ticket/10840:
  [ticket/10840] Add check_form_key to acp_groups.php
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/10840] Add check_form_key to acp_groups.php
Merge remote-tracking branch 'erangamapa/ticket/11145' into develop-olympus

* erangamapa/ticket/11145:
  [ticket/11145] Wrong error thrown when uploading a bigger image.
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11145] Wrong error thrown when uploading a bigger image.
[ticket/11586] Combine administrator/moderator checks together.

PHPBB3-11586
[ticket/11586] Use a variable for $cat_id == ATTACHMENT_CATEGORY_IMAGE.

PHPBB3-11586
[ticket/11586] Combine $filedata['post_attach'] assign into a single statement.

PHPBB3-11586
[ticket/11586] Move $filedata['thumbnail'] to where it might be returned.

PHPBB3-11586
Merge remote-tracking branch 'bantu/ticket/11586' into develop

* bantu/ticket/11586:
  [ticket/11586] Move $filedata['thumbnail'] to where it might be returned.
  [ticket/11586] Combine $filedata['post_attach'] assign into a single statement.
  [ticket/11586] Use a variable for $cat_id == ATTACHMENT_CATEGORY_IMAGE.
  [ticket/11586] Combine administrator/moderator checks together.