Issue #1862202 by plach, Berdir, katbailey, ParisLiakos, alexpott, chx, sun, larowlan, Gábor Hojtsy, cosmicdreams, vijaycs85, YesCT, penyaskito, andypost, Albert Volkman, joelpitett: Objectify the language system.

Issue #1786490 by Berdir, amateescu, damiankloip, Wim Leers, dawehner: Add caching to the state system.

Revert "Issue #1786490 by Berdir, amateescu, damiankloip, dawehner: Add caching to the state system."

This reverts commit 8ec847cc.

Issue #2019055 by plach, fago, berdir, yched, Gábor Hojtsy, kfritsche, jibran: Switch from field-level language fallback to entity-level language fallback.

Revert "Issue #2019055 by plach, fago, kfritsche: Switch from field-level language fallback to entity-level language fallback."

This reverts commit 46942cd3.

Issue #2019055 by plach, fago, kfritsche: Switch from field-level language fallback to entity-level language fallback.