* merged from debian/unstable

* merged from debian/unstable
* merge of the debian-expermental-ma branch
* refresh po/pot files in doc/ and po/
* Fix spelling error in cmdline/apt-get.cc. Thanks to Osamu Aoki
  Closes: #594211
* Swedish (Daniel Nylander). Closes: #592366
* French (Christian Perrier)
* Thai (Theppitak Karoonboonyanan). Closes: #592695
* Russian (Yuri Kozlov). Closes: #594232
* French (Christian Perrier)
* apt-pkg/contrib/strutl.cc:
  - fix error checking for vsnprintf in its safe variant
* methods/bzip2.cc:
  - fix error checking for read in case of failing bzip2/lzma/whatever
* debian/apt.cron.daily:
  - create backups for our extended_states file (Closes: #593430)
* apt-pkg/init.cc:
  - set the default values for dir::etc::trusted options correctly
* ftparchive/writer.cc:
  - init valid-until correctly to prevent garbage entering Release file
* apt-pkg/deb/debsystem.cc:
  - set dir::state::status based at least on dir
* apt-pkg/deb/dpkgpm.cc:
  - use the InstVer instead of the CurrentVer for the autobit transfer
* methods/http.cc:
  - some http servers violate HTTP1.1 by not issuing a Reason-Phrase
    (or at least a space after the code) especially for 200, but lets
    be nice and ignore it as we don't need the reason in general
* apt-pkg/acquire-item.cc:
  - don't use ReadOnlyGzip mode for PDiffs as this mode doesn't work
    in combination with the AddFd methods of our hashclasses