Issue #2572613 by Malevi4, idebr, pfrenssen, Mile23, RajeevK: Fix 'Drupal.Array.Array.CommaLastItem' coding standard

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 #2770921 by dawehner, klausi, Mile23, mpdonadio, xjm, claudiu.cristea: Feb 21st: Convert chunk of WTB to BTB by just moving classes, changing use statements adding traits