Added a question to README.md

Have you tried using Python 3? If I edit runtime.txt, I can upgrade to python-2.7.6 on IBM BlueMix with no problems.

However if I attempt python-3.4.0 or 3.3.0 I get the message File “/tmp/buildpacks/heroku-buildpack-python/vendor/bpwatch/bpwatch.zip/bp_cli.py”, line 37
print get_state()

The problem is that print() is a function in Python3 so the syntax must be print(get_state()) for Python3 to be happy. (e.g. In Python3 the parentheses are not optional).