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

Issue #2935256 by Jo Fitzgerald, voleger, kim.pepper, ibustos, Yogesh Pawar, catch, jibran: Remove all usages of drupal_get_message and drupal_set_message in modules

Issue #2901726 by mfernea, gmario, finn.lewis, robertoperuzzo, rachel_norfolk: Fix 'Squiz.Functions.MultiLineFunctionDeclaration' coding standard

Issue #2901739 by andriyun, Jo Fitzgerald, mfernea, xjm: Fix 'Squiz.Arrays.ArrayDeclaration' 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 #2719695 by alexpott, Mile23: Fix 'Drupal.Classes.ClassDeclaration.CloseBraceAfterBody' coding standard

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

Issue #2493911 by dawehner, larowlan, damiankloip, hussainweb, jibran, cilefen, benjy, iMiksu, mtdowling: Update guzzle, goutte and mink-goutte-driver to the latest release

Issue #2272481 by herom, ParisLiakos, tim.plunkett: Remove usages of watchdog() from forms, plugins and controllers.

Issue #1957330 by ParisLiakos, twistor: Make possible for parsers and fetchers to expose configuration through plugins.

Issue #1847002 by tim.plunkett, effulgentsia, msonnabaum: Move entity type classes from Drupal$provider\Plugin\Core\Entity to Drupal$provider\Entity.

Issue #1906692 by Simon Georges, jmarkel: String cleanup: make strings consistent in DefaultFetcher::fetch.

Issue #1937600 by Berdir, rootatwc | webchick: Determine what services to register in the new Drupal class.

Issue #1849752 by effulgentsia, Berdir, jibran, neclimdul: Abstract non-Drupal-specific parts of AnnotatedClassDiscovery into a Drupal\Component base class.

Issue #293318 by alex_b, Berdir, rootatwc, Aron Novak, mustafau, akahn: Convert Aggregator feeds into entities.

Issue #1447736 by rbayliss, mikeytown2, effulgentsia, kim.pepper, Fabianx, boombatower: Adopt Guzzle library to replace drupal_http_request().

- Patch #1683644 by chx, EclipseGc, tim.plunkett, aspilicious, xjm, dawehner, effulgentsia: use Annotations for plugin discovery.

- Patch #1497366 by neclimdul, effulgentsia, EclipseGc, merlinofchaos: introduce Plugin System to core.