Allow to specify credentials with non-ASCII characters during setup

[passiomatic]

Something like this in command_setup would work:

username, email, password = map(decode, [username, email, password])

The decode function should use the sys.stdin.encoding value to decode str to unicode glyphs. Note that checking UTF-8 encoded str for length > MIN_PASSWORD_LENGTH is not reliable. We should really convert str to unicode and then check for length.