- Fix the newly introduced method GetListOfFilesInDir to not
    accept every file if no extension is enforced
    (= restore old behaviour). (Closes: #565213)
* apt-pkg/policy.cc:
  - accept also partfiles with "pref" file extension as valid
* apt-pkg/contrib/configuration.cc:
  - accept also partfiles with "conf" file extension as valid
* doc/apt.conf.5.xml:
  - reorder description and split out syntax
  - add partfile name convention (Closes: #558348)
* doc/apt_preferences.conf.5.xml:
  - describe partfile name convention also here
* apt-pkg/deb/dpkgpm.cc:
  - don't segfault if term.log file can't be opened.
    Thanks Sam Brightman for the patch! (Closes: #475770)
* doc/*:
  - replace the per language addendum with a global addendum
  - add a explanation why translations include (maybe) english
    parts to the new global addendum (Closes: #561636)
* apt-pkg/contrib/strutl.cc:
  - fix malloc asseration fail with ja_JP.eucJP locale in
    apt-cache search. Thanks Kusanagi Kouichi! (Closes: #548884)