Issue #2571817 by Cottser, hussainweb: Remove race condition handling in TwigEnvironment::loadTemplate(), it's fixed upstream now

Issue #2568171 by Cottser, dawehner, hussainweb, Wim Leers, cilefen, znerol: Upgrade to Twig 1.22 and implement our own cache class

Issue #2568085 by plach, alexpott, dawehner, Berdir: Lock Twig on ~1.21.2 until we are able to upgrade to 1.22.0

Issue #2444615 by borisson_, neclimdul, jibran, dawehner, jhedstrom, Fabianx: Move testing packages to require-dev in composer.json

Issue #2546618 followup by plach: Document that we don't depend on the Symfony Translation component.

Issue #2546618 by plach, dawehner, chx, bojanz: Replace the Symfony Translation component with a custom interface since we don't use it

Issue #2429617 by Wim Leers, Fabianx, Berdir, yched, dawehner, effulgentsia, catch, borisson_, jhodgdon, martin107, torgosPizza: Make D8 2x as fast: Dynamic Page Cache: context-dependent page caching (for *all* users!)

Issue #2105825 by cosmicdreams, larowlan, hussainweb, Nitesh Sethia, dawehner, naveenvalecha, iMiksu: Update Doctrine/common Component to 2.5.1 (security) (includes cache/annotations too)

Issue #2498599 by Cottser, naveenvalecha, webchick, karolus, cilefen: Remove sdboyer/gliph since it is unused by core

Issue #2493911 by dawehner, larowlan, damiankloip, hussainweb, jibran, cilefen, benjy, iMiksu, mtdowling: Update guzzle, goutte and mink-goutte-driver to the latest release

Issue #2508231 by timmillwood, amateescu, hussainweb, catch, dawehner, David_Rothstein, Mixologic, effulgentsia: Raise minimum required version of PHP to 5.5.9

Issue #2343035 by fago, dawehner, larowlan, ianthomas_uk, cilefen, hussainweb, Miroling, jibran, beejeebus, dashaforbes, webmozart, klausi: Upgrade validator integration for Symfony versions 2.5+

Issue #2429363 by babruix, twistor, filijonka, sun, Mile23, daffie, Wim Leers, chx: Add HTML5-lib to Drupal 8 core for the filter system and for the testing system

Issue #2433009 by hussainweb, grom358, neclimdul, daffie, larowlan, alexpott, pcambra, benjy, jibran, phenaproxima, moshe weitzman, nick_schuch: Add Mink, with Goutte driver, to core

Revert "Issue #2433009 by hussainweb, grom358, neclimdul, daffie, larowlan, alexpott, pcambra, benjy, jibran, phenaproxima, moshe weitzman, nick_schuch: Add Mink, with Goutte driver, to core"

Oops. Accidentally committed the composer-only patch.

This reverts commit d653d386.

Issue #2433009 by hussainweb, grom358, neclimdul, daffie, larowlan, alexpott, pcambra, benjy, jibran, phenaproxima, moshe weitzman, nick_schuch: Add Mink, with Goutte driver, to core

Revert "Issue #2433009 by hussainweb, grom358, daffie, larowlan, alexpott, pcambra, benjy, jibran, phenaproxima, moshe weitzman, nick_schuch: Add Mink, with Goutte driver, to core"

This reverts commit 2b96082d.

Issue #2433009 by hussainweb, grom358, daffie, larowlan, alexpott, pcambra, benjy, jibran, phenaproxima, moshe weitzman, nick_schuch: Add Mink, with Goutte driver, to core

Issue #2253593 by neclimdul, damiankloip: Stop classloader searching filesystem for classes before drupal_classloader() is called

Issue #2375997 by Mile23, hussainweb, tstoeckler, omers: Avoid tying Drupal 8's composer.json to specific package commits