debian/control: Depend on perl instead of perl-modules

The perl-modules package is an implementation detail, depend on perl
instead.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Release version 0.12

Bump the version in configure.ac, and add news items to
debian/changelog.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>