Add an anchor free detection in YOLOV4
This project is almost the same with the source version of https://github.com/Tianxiaomo/pytorch-YOLOv4 The only difference is that I add an anchor-free detection in addition to the 3 based anchor of yolo. It worked on my own dataset with more than 3 per sent promotion of mAP on validation. Too busy to improve my code but I'll do that when I'm free. —— _ ——