small cahnges to examples

scan.py runs unchanged with python3
owget still has to be modfied due to different str/bytes semantics
release 0.7.2
Add support for handling ping responses on long op's

When owserver is busy (i.e. high load/contention, or long ops), it will
send ping frames every second or so.
preparing to merge pull requests
Merge branch 'pingfix' of https://github.com/stromnet/pyownet
tests.py has a config file tests.ini

* created config file for unit test suite tests.py
* reformatted code (better indents)
release 0.7.3
Merge branch 'master' into sensors