Issue #2638856 by bojanz, webflo, SiliconMind: Unable to install modules with core dependencies via composer

Revert "Issue #2550519 by klausi, nullkernel, cweagans, alexpott, pwolanin, neclimdul: Crypt::randomBytes() doesn't actually return cryptographically secure random bytes"

This reverts commit 51061769.

Issue #2550519 by klausi, nullkernel, cweagans, alexpott, pwolanin, neclimdul: Crypt::randomBytes() doesn't actually return cryptographically secure random bytes

(cherry picked from commit 1aa1fbe2)

(cherry picked from commit 96808b3a)

Issue #1269780 by hswong3i, damien_vancouver, Agileware, ricardoamaro, alexpott, axel.rutz, yannickoo: Remove symlinks option from .htaccess

Issue #2600176 by alexpott, dawehner, tim.plunkett: Step 1.875: Include the PhantomJS Mink driver for real

Issue #2592367 by alexpott: PHPUnit is broken - we have dependencies on Symfony event dispatcher tests

Issue #2585165 by pwolanin, alexpott, tarekdj, geertvd, dawehner, greggles: Don't include vendor test code (especially mink) in the Drupal webroot

Issue #2576037 by unqunq, er.manojsharma, sdstyles, martins.kajins, Devaraj johnson, cilefen, Bojhan, Wim Leers: "Sorry" in user-facing errors violates the User Interface Standards

Issue #2380389 by webflo, Mile23, davidwbarratt, timmillwood, hussainweb, tstoeckler, bojanz, yched, MKorostoff, alexpott, webchick: Use a single vendor directory in the root