cronwrap3 - simple but effective

I've used the cronwrap 1.4 in the past, and I always appreciated it's simplicity and effectiveness.

Unfortunately, it was never updated to work with Python3, and the developer seems to be unavailable anymore.

There is no git repository that I can find, so no way to fork it or submit a patch.

Finally, I just copied the code, and made a cronwrap3. It's basically the same code, with the print statements converted to print functions.