update template files.

* Improve menu toggle accessibility.
see https://github.com/Automattic/_s/commit/e142af3a2720e38179e294181562c22842a68c3e

* Use `div`s consistently throughout templates.
see https://github.com/Automattic/_s/commit/6c783cd09f68137f1ee0ec6dda1e7d9b0d79c8ec

* _s: Introduce 4.1 archive template tags.
see https://github.com/Automattic/_s/commit/bb867c0fcb2cfbae298d44a87c0638c75b8739f8

* update language files.
see https://github.com/gatespace/_s/commit/1228ca58721b64438712d9461369583d95ee30bb