* apt-pkg/acquire.cc:

* apt-pkg/acquire.cc:
  - make the max pipeline depth of the acquire queue configurable
    via Acquire::Max-Pipeline-Depth
* apt-pkg/deb/dpkgpm.cc:
  - add Dpkg::UseIoNice boolean option to run dpkg with ionice -c3
    (off by default)
  - send "dpkg-exec" message on the status fd when dpkg is run
  - provide DPkg::Chroot-Directory config option (useful for testing)
  - fix potential hang when in a backgroud process group
* apt-pkg/algorithms.cc:
  - consider recommends when making the scores for the problem
    resolver
* apt-pkg/acquire-worker.cc:
  - show error details of failed methods
* apt-pkg/contrib/fileutl.cc:
  - if a process aborts with signal, show signal number
* methods/http.cc:
  - ignore SIGPIPE, we deal with EPIPE from write in
    HttpMethod::ServerDie() (LP: #385144)
* apt-pkg/indexcopy.cc:
  - support having CDs with no Packages file (just a Packages.gz)
    by not forcing a verification on non-existing files
   (LP: #255545)
  - remove the gettext from a string that consists entirely
    of variables (LP: #56792)
* apt-pkg/cacheiterators.h:
  - add missing checks for Owner == 0 in end()
* apt-pkg/indexrecords.cc:
  - fix some i18n issues
* apt-pkg/contrib/strutl.h:
  - add new strprintf() function to make i18n strings easier
  - fix compiler warning
* apt-pkg/deb/debsystem.cc:
  - make strings i18n able
* fix problematic use of tolower() when calculating the version
  hash by using locale independant tolower_ascii() function.
  Thanks to M. Vefa Bicakci (LP: #80248)
* build fixes for g++-4.4
* cmdline/apt-mark:
  - add "showauto" option to show automatically installed packages
* document --install-recommends and --no-install-recommends
  (thanks to Dereck Wonnacott, LP: #126180)
* Updated cron script to support backups by hardlinks and
  verbose levels.  All features turned off by default.
* Added more error handlings.  Closes: #438803, #462734, #454989,
* Refactored condition structure to make download and upgrade performed
  if only previous steps succeeded. Closes: #341970
* Documented all cron script related configuration items in
  configure-index.
* apt-ftparchive might write corrupt Release files (LP: #46439)
* Apply --important option to apt-cache depends (LP: #16947)