Issue #2225399 by marcvangend, yanniboi, mr.baileys, Wim Leers, visabhishek: Apply formatters and widgets to Feed base fields.
Issue #2227513 by e0ipso, Wim Leers: Apply formatters and widgets to Shortcut base fields.
Issue #2202401 by Berdir: Make getPropertyDefinition() return NULL instead of FALSE.
Issue #2226437 by fago, tstoeckler, mauzeh: Create ContentEntityTypeInterface.