Merge with Matt

Merge with Matt

Patches applied:

 * apt@packages.debian.org/apt--main--0--patch-97
   Update priority of apt-utils to important, to match the override file

 * apt@packages.debian.org/apt--main--0--patch-98
   Install only one keyring on each branch (Closes: #316119)

 * apt@packages.debian.org/apt--main--0--patch-99
   Finalize 0.6.39

 * apt@packages.debian.org/apt--main--0--patch-100
   Use debian.org address in mainline

 * apt@packages.debian.org/apt--main--0--patch-101
   Update pot file

 * apt@packages.debian.org/apt--main--0--patch-102
   Open 0.6.40

 * apt@packages.debian.org/apt--main--0--patch-103
   Patch from Jordi Mallach to mark some additional strings for translation

 * apt@packages.debian.org/apt--main--0--patch-104
   Updated Catalan translation from Jordi Mallach