* faster and more informative training plots
* Update utils.py
Looks good. Needs pep8 linting, I'll do that in PyCharm later once PR is in.
* Update test.py
* Update train.py
f for the tb descriptor lets us plot several batches, i.e. to allow us to change L292 to 'if ni < 3' for 3 examples.
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>