Use composer generated autoloader in <root>/vendor/
Add composer.json from drupal project
Merge branch '8.0.x-patches' into 8.0.x-composer

Conflicts:
	composer.json
	vendor/autoload.php
Issue #2359509 by Berdir: Incorrect type safe check in Entity::onUpdateBundleEntity() results too many cache clears
Issue #2389275 by bforchhammer: Views render element #embed not working