Lots of good stuff in here.

Python 3.5 may actually be what finally convinces me to move to Python 3 (that, and the end of Python 2.7 support coming up in a few years).

The new async stuff, finally fixing some of the problems with byte strings that made them not really an adequate replacement for Python 2.x strings, and os.scandir is a substantial performance improvement over os.listdir plus calls to stat (though os.scandir, at least, is also available in Python 2.7 via PyPI).