Merge branch 'devel' into feature/create-additional-software-config
additional software: do not crash when tails is used without persistence

Before this, tails-additional-software crashed if there was no
persistent volume activated. It now exits gracefully.
Fetch poedit from squeeze-backports-sloppy.

Note: this commit alone actually won't trigger the intended effect until we drop
our own poedit package from deb.t.b.o.
Merge remote branch 'origin/devel' into feature/create-additional-software-config
Install Pidgin from squeeze-backports (Closes: #6661).
Merge branch 'feature/6661-pidgin-2.10.9' into devel
Merge branch 'feature/poedit-from-backports' into devel

Conflicts:
	config/chroot_apt/preferences
Merge branch 'feature/create-additional-software-config' into devel
Simplify Pidgin's APT pinning, now that our APT suite was cleaned up.