* Add nano model to the download list

* Add possibility to also download the "*6" models

* Cleanup

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

* Implement new headers

* Reformat 1

* Reformat 2

* Reformat 3 - math

* Reformat 4 - yaml

* Update download script headers

* cleanup

* bug fix attempt

* bug fix attempt2

* bug fix attempt3

* cleanup

* Remove `/weights` directory

* cleanup