added new WallMessage::getETag() method, WallHooksHelper::onParserCacheGetETag() hook and invalidating page_touched for parent message in MessageWall
simplified logic in WallHooksHelper::onParserCacheGetETag()
added ?action=history pages to purge URLs list
added new method WallMessage::invalidateCache() and fires it in different Wall actions
refactored WallMessage::invalidateCache(), fixed WallMessage::getSquidURLs() so it sends history page of a newly created thread on MessageWall
used the same approach as in Wall for Forum; new hook ForumHooksHelper::onParserCacheGetETag
purging board page and its history page
backported from dev: BAC-1346 remove dependency on $wgEnableCentralizedLogging - no reason to ever have it disabled
nicer way to concatenate strings
resign from hook approach in favor of PageOutput::setETag()
removed unused variables
back to the roots
added WallMessage::invalidateMessagePageCache() and invalidate MessageWall title once an action on wall happens: adding, editing, removing, deleting thread/reply
resigned from hook approach; changes in WallbaseController handles also Forum
clean up
code review changes: moved invalidateCache() call to purgeSquid()
Merge pull request #2929 from Wikia/CONN-430

CONN-430