Depend on dconf-config

- Add a dependency on debathena-dconf-config, since we're using
  the 'athena' dconf db
Convert to dh7 and clean up maintscripts

- Convert rules file to dh7
- Wrap Build-Depends in control file
- Remove c-p-d shell snippets from maintainer scripts
- Remove rm_conffile snippets and switch to dpkg-maintscript-helper (and
  Pre-Depend on the right version of dpkg for that)
Move to per-distro override files

- Because of incompatible settings (I'm looking at you, Unity) and
  deprecated ones, we need per-distro override files.
- Add code to rules file to create the actual override file at build
  time based on the distro, and Depend on lsb-release
Release 1.41