Improve debian packaging (#47) * debian: switch to debhelper-compat and compat 13 * d/control: remove very old Breaks/Replaces not needed anymore * d/control: bump standard-version to 4.6.2 * d/copyright: improve header fields * d/control: some improvements - specify that rules don't require root - add homepage with repository url - merge extended description from Debian packages: specify when translations is done