master.lmde6

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