text: Title: Support of Batch Input
  Body: Hi, 
  
  it appears that the original code did not directly support the batch input. I forked the repo and created some simple modification. (you may discard the part to load my own models)
  https://github.com/CielAl/pytorch-grad-cam_batch/blob/master/grad_cam.py#L114
  
  Hope this might be useful in case others try to apply your implementation :)))