Ugly: Bogus dependency on libotr2-dev, but adding a warning to the configure
script that this actually won't work.

This because I can't figure out how to make a source dependency conditional
on whether a certain binary packages is going to be built. It's kind of okay
since libotr2-dev is unavailable on new systems anyway.
Update debian/changelog for 3.2.1.
3.2.1-1 Debian package.
Fix building of debug binaries (partially broken by changeset:devel,253).