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

Issue #2347799 by andypost, almaudoh, znerol: Remove bugged session-related methods from AccountInterface

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