Issue #2776975 by joelpittet, dawehner, tim.plunkett, xjm, pfrenssen: March 3, 2017: Convert core to array syntax coding standards for Drupal 8.3.x RC phase

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

Issue #2426031 by almaudoh, cpj: Remove deprecated uses of SessionManager::isEnabled(), SessionManager::enable() and SessionManager::disable()

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