Version bump v1.2

Should have done this when splitting off the maint branch, but alas!
doc bug: Fixup the README
Bug: Python-3 support for password authentication

Encode the username and password as UTF-8 byte-strings before doing
base64 encoding on them.

By rights, We ought to have been doing this encoding explicitly all
along. But in Python-3, failing to do so results in a TypeError, so we
can no longer claim naïveté.