BAC-177: use datamart in RenameUserHelper
BAC-177: use rollup_edit_events in UserRollbackTask.class.php
remove unused tables (BAC-335)
Merge branch 'dev' into bac-177-stats-events
Revert "BAC-177: use rollup_edit_events in UserRollbackTask.class.php"

This reverts commit 8271acfb17e82b353db6b0081b51c018621a6eae.
Merge pull request #942 from Wikia/bac-177-stats-events

BAC-336: Use datamart in RenameUserHelper
BAC-336: use GROUP BY instead of DISTINCT
Merge pull request #943 from Wikia/bac-177-stats-events

BAC-336: use GROUP BY instead of DISTINCT
BAC-322: add log backtrace for "MySQL server has gone away" errors
Merge pull request #947 from Wikia/bac-322-log-gone-aways

BAC-322: add log backtrace for "MySQL server has gone away" errors
(CE-48) Staff with admin rights should use admin welcomes
Merge branch 'CE-48' into dev
Merge branch 'dev' into responsive-layout