[ticket/11760] Use phpbb_version_compare() wrapper

PHPBB3-11760
[ticket/11801] removed some whitespace and added missing semi colon's in css

PHPBB3-11801
Merge remote-tracking branch 'Elsensee/ticket/11760' into develop

# By Oliver Schramm
# Via Oliver Schramm
* Elsensee/ticket/11760:
  [ticket/11760] Use phpbb_version_compare() wrapper
Merge remote-tracking branch 'Prosk8er/ticket/11801' into develop-olympus

* Prosk8er/ticket/11801:
  [ticket/11801] removed some whitespace and added missing semi colon's in css
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11801] removed some whitespace and added missing semi colon's in css

Conflicts:
	phpBB/styles/prosilver/theme/colours.css
[ticket/11802] replace $browser with $user->browser

PHPBB3-11802
Merge remote-tracking branch 'dhruvgoel92/ticket/11802' into prep-release-3.0.12

* dhruvgoel92/ticket/11802:
  [ticket/11802] replace $browser with $user->browser
Merge branch 'prep-release-3.0.12' into develop-olympus

* prep-release-3.0.12:
  [ticket/11802] replace $browser with $user->browser
Merge branch 'develop-olympus' into develop

* develop-olympus:
  [ticket/11802] replace $browser with $user->browser

Conflicts:
	phpBB/download/file.php
[ticket/11804] Remove </li> from overall_header which was not open

PHPBB3-11804
Merge remote-tracking branch 'mvinny/ticket/11804' into develop

* mvinny/ticket/11804:
  [ticket/11804] Remove </li> from overall_header which was not open
Merge remote-tracking branch 'upstream/develop' into develop