Issue #2363741 by joelpittet: Upgrade Twig to 1.16.* from 1.15.*.

composer.json

composer.lock

core/vendor/composer/installed.json

core/vendor/twig/twig/.travis.yml

core/vendor/twig/twig/CHANGELOG

core/vendor/twig/twig/composer.json

core/vendor/twig/twig/doc/api.rst

core/vendor/twig/twig/doc/deprecated.rst

core/vendor/twig/twig/doc/filters/batch.rst

core/vendor/twig/twig/doc/filters/convert_encoding.rst

core/vendor/twig/twig/doc/filters/first.rst

core/vendor/twig/twig/doc/filters/json_encode.rst

core/vendor/twig/twig/doc/filters/last.rst

core/vendor/twig/twig/doc/filters/length.rst

core/vendor/twig/twig/doc/filters/merge.rst

core/vendor/twig/twig/doc/filters/nl2br.rst

core/vendor/twig/twig/doc/filters/number_format.rst

core/vendor/twig/twig/doc/filters/raw.rst

core/vendor/twig/twig/doc/filters/slice.rst

core/vendor/twig/twig/doc/filters/split.rst