BugId:51338 HAWelcome Minor fix.
Merge pull request #619 from Wikia/fb51338-hawelcome-minor-fixes

BugId:51338 HAWelcome Minor fix.
BugId:51338 HAWelcome Minor fix.
Merge pull request #620 from Wikia/fb51338-hawelcome-minor-fixes

BugId:51338 HAWelcome Minor fix.
Use static method variable cache for AdEngine2Controller::getExitstitialUrlsWhiteList
ADEN-7 Introducing $wgEnableAdEngineExt
ADEN-7 Ad template
ADEN-7 Proxy Ad_Index to AdEngine2_Ad
ADEN-7 Move more logic to AdEngine2Controller
ADEN-7 Remove per-slot logic in AdEngine2Controller
ADEN-7 Removing TOP_RIGHT_BUTTON slot
ADEN-7 Introducing logic to determine slots appearance
ADEN-7 Massive AdEngine.php clean up

Conflicts:
	extensions/wikia/AdEngine/AdEngine2Controller.class.php
ADEN-7 Move getLiftiumOptionsScript to AdEngine2Controller
ADEN-7 Removing random dependencies on AdEngine
ADEN-7 Re-add DART key values to LiftiumOptions
ADEN-7 Added TODO for hubs category caching
ADEN-7 Removing PartnerWidget

Conflicts:
	extensions/wikia/AdEngine/PartnerWidget.php
ADEN-7 Removing last parts of AdEngine.php

Conflicts:
	includes/wikia/GlobalFunctions.php
ADEN-7 Show ads only on content and extra namespaces