- epm play: add cnrdrvcups-ufr2 support
- epm repo add/remove: add korinf support
- erc-sh-archive: add diag message if backend is missed
- erc-sh-archive: add checking for 7zr and 7zz
- epm-sh-functions erc(): check if some erc backend is installed and install p7zip if missed
- epm-repack: add p7zip require
- allow EPM_BACKEND and SERV_BACKEND to force backend to use
- epm-release_upgrade: remove apt-conf-sisyphus only if installed