Fix various colorization issues in Monobook

This commit addresses several color problems in the Forum and WikiaStyleGuide extensions caused by pulling colors set in the Theme Designer for the Oasis skin.
Fix out-of-place black background
Additional colorization fixes (VOLDEV-36)
code cleanup
VOLDEV-47 - Add select all button to Special:ListUsers
Merge branch 'dev' into VOLDEV-36

Conflicts:
	extensions/wikia/Forum/css/RelatedForumDiscussion.scss
enforced VOLDEV-36 changes
use .prop() over .removeAttr()
set check using .prop() too
Added basic Extension files
Added template
Date
Added new lines
Tabs
Added translation
VOLDEV-36: Separate Monobook styling
VOLDEV-36: include mixins
Correct $wgExtensionCredits key
Basic page styling
New line in scss
Fixed typo