Merge branch 'experimental' into pu

* experimental:
  xz-utils/README.Debian: flesh out "differences from upstream"
  liblzma: Check that the first byte of range encoded data is 0x00.
  xz: Fix the version number printed by xz -lvv.
  xz: Update the man page about the new field in --robot -lvv.
  xz: Update man page date to match the latest update.
  debian/control: xz-utils is not pseudo-essential any more
  xz-utils/README.Debian: Document patches

Conflicts:
	debian/changelog
	debian/xz-utils.README.Debian