Converted script to use str.format instead of using the older operator
(%s, %d and so on).

It should be fine as it is, but I want to be sure before merging and
updating the version number to 0.7.
Stripped out commented old code since initial tests pass and
comparison wth master copies are easy.
Version 0.7.0:

Script passes all tests in foad.py -f unittest with new string
handling format.  Prepared to release as version 0.7.

Also, preliminary testing indicates the script works with PyPy3
(2.3.1).  Not enough testing has been done yet to claim that as
guaranteed, though.