Issue #2705809 by juampynr, dawehner, damiankloip, lahoosascoots: Queue garbage collection is not correctly run on cron

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #287292 by almaudoh, mr.baileys, drewish, Berdir, znerol, boombatower, dawehner, jpetso, floretan: Add functionality to impersonate a user

Issue #2038275 by tim.plunkett, mr.baileys, Sam Hermans: Convert hook_queue_info() to plugin system.

Issue #2319177 by swentel, fago: Fixed Cron lock time limit is too short and does not prevent multiple, concurrent cron runs.

Issue #2271251 by ParisLiakos, undertext, JeroenT, StevenPatz, tim.plunkett: Remove usages of watchdog() from non-form and non-controllers.

Issue #1524550 by superspring, joachim, David Hernández, marthinal, socketwench, subson | jfinkel: Fixed queue cron workers can't signal a broken queue.

Issue #2228341 by sun, znerol, skipyT, ParisLiakos: Objectify session management functions + remove session.inc.

Issue #2180109 by damiankloip, dawehner, ParisLiakos, joelpittet, MartijnBraam, Xano: Change the current_user service to a proxy.

Issue #2178581 by damiankloip, penyaskito, Solthun: Add an AnonymousUserSession object in favour of using drupal_anonymous_user().