Issue #1754246 by webflo, swentel, penyaskito, andypost, alexpott, YesCT, dagmar: Languages should be configuration entities.

Issue #1813762 by ParisLiakos, Jose Reyero, YesCT, japicoder, attiks: Introduce unified interfaces, use dependency injection for interface translation.

Issue #1818570 by Berdir, effulgentsia, das-peter, andypost: Convert users to the new Entity Field API.

Issue #1620010 by dawehner, ParisLiakos, plach, jibran: Move LANGUAGE constants to the Language class.

Issue #1751348 by heyrocker, vijaycs85, julien, Gábor Hojtsy: Convert locale settings to configuration system.

Issue #1899994 by katbailey, plach, YesCT: Disentangle language initialization from path resolution.

Issue #1714462 by n3or, sun, Gábor Hojtsy: Convert language negotiation settings to configuration system.

Issue #1739928 by vasi1186, YesCT, webflo, Transition, plach, Gábor Hojtsy: Generalize language configuration on content types to apply to terms and other entities.

Revert "Issue #1588422 by andypost, disasm, sun, dawehner, vasi1186, alexpott, tim.plunkett, larowlan, Gábor Hojtsy: Convert contact categories to configuration system."

This reverts commit 5cb63c4d.

Oops. That was a little more patch than we bargained for. :P

Issue #1588422 by andypost, disasm, sun, dawehner, vasi1186, alexpott, tim.plunkett, larowlan, Gábor Hojtsy: Convert contact categories to configuration system.

Issue #1739994 by pp, das-peter, Gábor Hojtsy: Use the Language class universally instead of stdObj instances.

Issue #1711070 by kid_icarus, tim.plunkett, xjm, droplet, zendoodles and cam8001: Convert tests to use ::$modules property instead of parent::setUp($modules).

Using the language_manager wrapper function to return a language whether or not we're in the requet scope

Issue #258785 by Désiré, Schnitzel, kbasarab, pkiraly, desbeers, Bojhan, voxpelli, clemens.tolboom, Artusamak, Gábor Hojtsy, dvinegla: Added Provide more flexible settings for initial language on content types.

Issue #1452188 by Schnitzel, droplet, Sutharsan, Bojhan, Kristen Pol, Gábor Hojtsy, ershov.andrey, perusio, nod_, rvilar, andypost: Added New UI for string translation.