Issue #2457887 by prateekMehta, stefan.r, rpayanm, alexpott: Use Utility\SafeMarkup class instead of Utility\String for placeholder(), checkPlain(),format() functions

Issue #2164601 by yched, jibran, amateescu, pfrenssen: Stop auto-creating FieldItems on mere reading of $entity->field[N]

Issue #2143729 by tstoeckler, plach, jsbalsera, Berdir, mauzeh, damiankloip, andypost: Entity definitions miss a language entity key

Issue #2340667 by YesCT, Pedro Lozano, alexpott, martin107: Protect Drupal\Core\Language\Language::id, and use getId().

Issue #1966436 by naveenvalecha, cesarmiquel, Berdir, mr.york, jlbellido, segi, vasi1186, Leksat, Gábor Hojtsy, Schnitzel, grisendo, Aron Novak, likin, penyaskito, vijaycs85, kfritsche, fago: Fixed Default *content* entity languages are not set for entities created with the API.

Issue #697760 by sun: Replace getInfo() in tests with native phpDoc + annotations (following PHPUnit).

Issue #2246665 by jaredsmith, martin107, YesCT, filijonka, tstoeckler: Typehint with Drupal\Core\Language\LanguageInterface instead Drupal\Core\Language\Language.

Issue #1969572 by neclimdul, larowlan, hussainweb, dawehner, damiankloip, ParisLiakos, pwieck, Berdir, socketwench: Make Uuid a service.

Issue #1777956 by fago, klausi, sun, dasjo: Provide a way to define default values for entity fields.