* add dice evaluation metric
* add dice evaluation metric
* add dice evaluation metric
* support 2 metrics
* support 2 metrics
* support 2 metrics
* support 2 metrics
* fix docstring
* use np.round once for all
* fix acc and iou compute nan problem
* fix acc and iou compute nan problem
* add nan_to_num args for mean_iou
* add nan_to_num args for mean_iou
* add nan_to_num args for mean_iou
* add nan_to_num args for mean_iou
* add nan_to_num args for mean_iou
* Update mmseg/core/evaluation/mean_iou.py
* Update mean_iou.py
* Update mean_iou.py
Co-authored-by: Jerry Jiarui XU <xvjiarui0826@gmail.com>