Created by: ZhaoFour

There's 13 ops are not supported yet =========== mul_grad =========== =========== cross_entropy_grad2 =========== =========== sum =========== =========== cross_entropy2 =========== =========== relu6_grad =========== =========== adam =========== =========== mean_grad =========== =========== elementwise_add_grad =========== =========== conv2d_grad =========== =========== depthwise_conv2d_grad =========== =========== pool2d_grad =========== =========== batch_norm_grad =========== =========== softmax_grad ===========