refactoring $*#&*# Python

Once again, into the Pyth circle of hell. This time trying to convert our code from Python 2 to 3. 2to3 does much fo the grunt work of print() and 'from . import', though it didn't always get the latter right. But instead of string and unicode, we now have string and bytes value types, and a strong barrier between them. And of course no static compiler to find up front when types might be mixed up. And yes, we're weak on unit tests, especially tests that exercise all possible code paths. Things seem to mostly work now, but will they under all conditions? Who knows?