Merge branch 'master' into deploy

* master:
  Change dir before using R, seems to write out some Rplots.pdf in .
  Assume false if not defined
  acl deny: downgrade removing non-existing permissions to warning
  remove unused variable
  typo: modules (plural)
  fixup! request external signatures
  option to allow specific keys to upload source-only NEW packages
  add test for external signature requests
  update GNU/emacs kernel package
  request external signatures
  update-buildd-archive: also copy project/external-signatures directory
  acl: add subcommands to add/remove packages from per-source ACL
  config: add option to include other files