v0.1.1

1. Fix target transform error label2yolobox. #029f796
2. Add multi-GPUs training and update yolov2_voc.cfg and yolov2-tiny_voc.cfg training results. #6632949
3. Integrated COCO dataset and evaluator. #5b19877 #e1ba3ba

	Original (darknet)	tztztztztz/yolov2.pytorch	zjykzj/YOLOv2(This)	zjykzj/YOLOv2(This)
arch	YOLOv2	YOLOv2	YOLOv2	YOLOv2-tiny
train	VOC07+12 trainval	VOC07+12 trainval	VOC07+12 trainval	VOC07+12 trainval
val	VOC2007 Test	VOC2007 Test	VOC2007 Test	VOC2007 Test
VOC AP[IoU=0.50]	76.8	72.7	70.39	63.77
conf_thre	/	0.005	0.005	0.005
nms_thre	/	0.45	0.45	0.45
input_size	416	416	416	416