Merge branch 'master' into core-updates

Thank Cyrill.

Thank Matthias and Yutaka.

gnu: Add pspp.

* gnu/packages/maths.scm (pspp): New variable.
* THANKS: Thank John Darrington for help with debugging.

gnu: Add libextractor.

* gnu/packages/gnunet.scm: New module.
* gnu-system.am (GNU_SYSTEM_MODULES): Add module.
* THANKS: Thank Christian Grothoff for help with debugging.

Thank the translators.

Import (guix hash) in build-aux/download.scm.

* build-aux/download.scm: Import (guix hash).
  Reported by Matthew Lien <bluet@bluet.org>.

Fix name of Alexandru.

Thanks, Cojocaru.

Thank Lluís and Daniel.

Update `AUTHORS' and `THANKS'.

Update `THANKS'.

Update `THANKS'.

Move Andreas to `AUTHORS'.

Merge branch 'master' into nix-integration

Conflicts:
	guix/store.scm

Update `THANKS'.

Add `THANKS'.