Log Message:
py-xopen: updated to 0.7.3

v0.7.3:
Add PipedGzipReader.flush()
To Do: Perhaps derive from IOBase instead. See a Python implementation in
_pyio.

v0.7.2:
Skip test on Python 2.7
I don’t want to entirely give up Python 2.7 compatibility, yet, but I also
don’t want to spend time fixing this.