Replaced deprecated tkinter trace methods with new versions

[jstone-psi]

Fixes #136.

I've updated the tkinter code to use the new trace methods that were introduced in Python 3.6, which replace the deprecated versions that were recently removed.

[LevN0]

Thank you for reporting and submitting a PR Jesse.

This tool still supports Python 2.7 and 3.5 for now, so I think a bit more work is needed to do this in a compatible way (although support for 3.5 is likely to be dropped before the next release anyway). I can probably do that pretty quick when I have a moment.

[jstone-psi]

Understood. I was able to not break python 3.13 by checking for the presence of the trace_add function and branching based on that, but I'm not set up to test earlier versions of python. Hope this helps!

[jordanpadams]

As a note, Python 2.7 and 2.5 were EOL in 2020. Folks will clearly continue to run older versions of Python, but if that maintenance becomes too painful, an upgrade in system requirements, albeit painful for some, may help keep things moving forward.