Changes:
- add parameters nms_kind, nms_thresh, new_coords to yolo layer and darknet parser
- added diou nms, new method to compute the BBs
- created test for yolov4x-mish called yolo4x
Tested, all tests work.
Problem to solve: little loss in mAP of yolo4x
Signed-off-by: Micaela Verucchi <micaelaverucchi@gmail.com>