Issue #2873696 by nvexler, wengerk, gido, Jo Fitzgerald, xjm: Add @internal to core classes, methods, properties to Form Classes

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 #2429443 by vijaycs85, rteijeiro, penyaskito, gloob, xjm, nod_, geertvd, pjonckiere, alexpott, Wim Leers, Gábor Hojtsy, Fabianx, tim.plunkett: Date format form is unusable

Revert "Issue #2429443 by vijaycs85, rteijeiro, penyaskito, gloob, xjm, nod_, geertvd, Wim Leers, Gábor Hojtsy, Fabianx, pjonckiere, tim.plunkett: Date format form is unusable"

This reverts commit 37e278b4.

Issue #2429443 by vijaycs85, rteijeiro, penyaskito, gloob, xjm, nod_, geertvd, Wim Leers, Gábor Hojtsy, Fabianx, pjonckiere, tim.plunkett: Date format form is unusable

Issue #2022875 by Berdir, alexpott, Xano, swentel, tim.plunkett, vladan.me: Resolve difference between submitForm(), submit(), and save() in EntityFormController.

Issue #2149197 by penyaskito, mikey_p, vijaycs85, herom: Replace format_interval with \Drupal::service('date')->formatInterval().

Issue #1998140 by dawehner, ParisLiakos, tim.plunkett: Remove backward compatible ControllerInterface.