run 2to3 and manual convert for Python3

[hyphaltip]

This is python3 code update - it appears to work on python3 based on some basic tests.

if you drop it in will not quite work for python2 because of expected capitalization change: https://docs.python.org/2/library/configparser.html

File "Pangloss.py", line 89, in from configparser import SafeConfigParser

[hyphaltip]

You probably want to merge this into a python3 branch rather than master/main until you are ready to do a release for python3?

[hyphaltip]

But this should help solve #2