Relation Networks for object detection based pytorch

• add relation module
• add nms using relation module
• end to end train renet based faster-rcnn on VOC2007
• evaluate mAP
• modified learn_nms
• add OHEM
• improve performance
• train and forward on COCO

1. Python3.5
2. The following Python packages:

Cython
cupy
numpy
pytorch
opencv-python
collections

This work builds on many excellent works, which include:

• Yusuke Niitani's ChainerCV (mainly)
• Ruotian Luo's pytorch-faster-rcnn which based on Xinlei Chen's tf-faster-rcnn
• simple-faster-rcnn-pytorch by chenyuntc
• faster-rcnn.pytorch by Jianwei Yang and Jiasen Lu.It mainly refer to longcw's faster_rcnn_pytorch
• All the above Repositories have referred to py-faster-rcnn by Ross Girshick and Sean Bell either directly or indirectly.
• yhenon's pytorch-retinanet
• msracver's Relation-Networks-for-Object-Detection