[ticket/12233] Add images back to subsilver2

PHPBB3-12233
[ticket/12233] Update schema file

PHPBB3-12233
[ticket/12234] Replace ICQ with custom profile field

PHPBB3-12234
Merge branch 'develop-olympus' into develop

* develop-olympus:
[ticket/12238] Remove defunct confirmation box template code.

Confirmation boxes are handled by confirm_body.html.

PHPBB3-12238
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11509] Exit with the expected (non-zero) exit status on failure.
  [ticket/11509] Output which commit is being inspected.
  [ticket/11509] Three dots means sym. difference, but we only want new commits.

Conflicts:
	.travis.yml
Merge remote-tracking branch 'prototech/ticket/12238' into develop

* prototech/ticket/12238:
  [ticket/12238] Remove defunct confirmation box template code.
Merge remote-tracking branch 'rxu3/ticket/12222' into develop

* rxu3/ticket/12222:
  [ticket/12222] Replace hardoded comma with translatable separator
Merge pull request #2065 from prototech/ticket/12232

[ticket/12232] Remove excessive calls to sizeof() in assign_block_vars() method.
[ticket/12126] Fixed position of alert box in IE

PHPBB3-12126
[ticket/12126] Changed .phpbb_alert "max-width: 640px" to "width: 620px"

PHPBB3-12126
[ticket/12240] Added specific class name to posting buttons

PHPBB3-12240
[ticket/12240] Added class code for custom bbcodes based on bbcode_tag

PHPBB3-12240
[ticket/12240] Added template changes for subsilver2, too

PHPBB3-12240
[ticket/11693] Change sql_build_array to support DELETE

PHPBB3-11693
[ticket/11645] Rename .MODs tab in ACP to Extensions

http://tracker.phpbb.com/browse/PHPBB3-11645

PHPBB3-11645
[ticket/9255] Added max-height and overflow-x to cp-mini in cp.css

PHPBB3-9255
[ticket/9255] Changed overflow-x to overflow-y

PHPBB3-9255
[ticket/12126] left:0 and right: 0; admin.css --> width: auto

PHPBB3-12126
[ticket/12126] deleted left:0 and right:0 in responsive.css .phpbb_alert

PHPBB3-12126