Issue #1834594 by effulgentsia, Rob Loach: Update dependencies (Symfony and Twig).

core/composer.json

core/composer.lock

core/vendor/autoload.php

core/vendor/composer/autoload_classmap.php

core/vendor/composer/autoload_real.php

core/vendor/composer/installed.json

core/vendor/doctrine/common/composer.json

...trine/common/lib/Doctrine/Common/Annotations/DocLexer.php

...r/doctrine/common/lib/Doctrine/Common/Cache/FileCache.php

core/vendor/doctrine/common/lib/Doctrine/Common/Version.php

...class-loader/Symfony/Component/ClassLoader/.gitattributes

...ony/class-loader/Symfony/Component/ClassLoader/.gitignore

...s-loader/Symfony/Component/ClassLoader/ApcClassLoader.php

...r/Symfony/Component/ClassLoader/ClassCollectionLoader.php

...fony/class-loader/Symfony/Component/ClassLoader/README.md

...Component/ClassLoader/Tests/ClassCollectionLoaderTest.php

...ony/Component/ClassLoader/Tests/ClassMapGeneratorTest.php

...nt/ClassLoader/Tests/Fixtures/Namespaced/WithComments.php

...nent/ClassLoader/Tests/Fixtures/Pearlike/WithComments.php

.../Component/ClassLoader/Tests/UniversalClassLoaderTest.php