the python apt bindings

Merge proposals dependent on lp://qastaging/~jamesodhunt/python-apt/fix-for-PkgCacheGetIsMultiArch

  1. fix-for-PkgCacheGetIsMultiArch
  2. Dependent merge proposals

lp://qastaging/~jamesodhunt/python-apt/fix-for-PkgCacheGetIsMultiArch has no merge proposals.