• Rename the project and module to apt-smart
• For Ubuntu, new mirrors discovery mechanism: at first it queries MIRROR_SELECTION_URL, and MIRRORS_URL as fallback.
• For Debian, new mirrors discovery mechanism: get mirrors within the country which the user is in.
• New mechanism of determining whether a mirror is up-to-date: download the InRelease file and parse the Date value in it.
• New and more robust distribution_codename using APT sources.list
• Enable retry when fetch_url is timeout for bad connections.
• Drop Python 2.6 support and add Python 3.7
• Drop max_mirrors limit since we can smartly get mirrors within the user's country.