Issue #2935255 by Jo Fitzgerald, kim.pepper, voleger, alexpott, martin107, jibran, catch: Remove all usages of drupal_get_message and drupal_set_message in core lib

Issue #2572791 by Mile23, andriyun, attiks, RoSk0: Fix 'Drupal.WhiteSpace.OpenBracketSpacing' coding standard

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

Issue #2289917 by Wim Leers, mdrummond, lauriii, Manuel Garcia, emma.maria, Scionar, davidhernandez: Convert "messages" page element into blocks