project: https://github.com/PaddlePaddle/Paddle/issues/4531 - [x] img_conv [conv2d](https://github.com/PaddlePaddle/Paddle/blob/develop/python/paddle/v2/framework/layers.py#L189) - [x] img_pool [pool2d](https://github.com/PaddlePaddle/Paddle/blob/develop/python/paddle/v2/framework/layers.py#L241) - [x] drop_out layer https://github.com/PaddlePaddle/Paddle/pull/5134 - [ ] batch_norm layer https://github.com/PaddlePaddle/Paddle/pull/5192 - [ ] whole train file https://github.com/PaddlePaddle/Paddle/pull/5192