Merge from apt--mvo--0

Patches applied:

 * michael.vogt@canonical.com--2004--laptop/apt--mvo--0--patch-6
   * stronger dependencies for libapt-pkg-dev (depends on the source version of apt and apt-watch now)

 * michael.vogt@canonical.com--2004--laptop/apt--mvo--0--patch-7
   * distro really should be hoary, not unstable :/

 * michael.vogt@canonical.com--2004--laptop/apt--mvo--0--patch-8
   * documented the "--allow-unauthenticated" switch

 * michael.vogt@canonical.com--2004/apt--mvo--0--patch-2
   brought tree up-to-date with matt

 * michael.vogt@canonical.com--2004/apt--mvo--0--patch-3
   * imported changes from apt--main

 * michael.vogt@canonical.com--2004/apt--mvo--0--patch-4
   * merged changes from the conference