Zunzunsite3 web application updated to use Python logging module

[zunzun.com]

I have replaced some old print statements with calls using the standard Python logging module, *.log files (if any) will be written to the auto-cleaning temp file directory where the image and PDF files are written. This was done primarily to automatically get stack traces logged on any exceptions, though this Python module is quite nice to work with once it has been set up.

No changes to any program logic or calculations have been made, and all web site functionality tests pass with no problem. Users should see no change.

James

[zunzun.com]

The new logging has produced its first fruit - unknown to me, there was an obscure error where PDF files would not be created for the 2D User-Selectable Rational equations. This has been corrected, and if you run the site open source code use "pip3 install -U pyeq3" to get the change.

James