Add rank difference, and top-1/top-5 difference from ImageNet-1k validation for the 3 additional test sets

[KushajveerSingh]

Added rank_diff, top1_diff, top5_diff columns in the results of ImagenetV2 Matched Frequency, ImageNet-Sketch, ImageNet-Adversarial.

• +26.1 (for positive difference)
• -3 (for negative difference)
• = (for no change)

Added a script results/generate_csv_results.py, which can be used for updating the csv files in the future. Add dummy values in the {rank, top1, top5}_diff columns when making an entry for a new model.

To add a new result.csv file in the future, only the results dictionary in the script needs to be updated. (This assumes that rank_diff, top1_diff, top5_diff columns are already present in the csv file. I did not include the if checks for that in the pull request, as it needs to be only done once).

[rwightman]

@KushajveerSingh awesome thanks, something I've been meaning to do for some time. Just a minor tweak request on the decimal digits. Could you limit the topx and crop pct entries to 3 decimal digits and the param count to 2?

[KushajveerSingh]

Made the changes. Set precision of top1, top1_err, top1_diff, top5, top5_diff, top5_err, cropt_pct to 3 and param_count to 2.

Also, removed the TODO item from README.