Include Caffe model for Krizhevsky architecture (AlexNet)

The Caffe reference ImageNet model differs from the Krizhevsky architecture in the order of the LRN and max pooling layers. The `caffe_alexnet_model` is the Krizhevsky architecture; however, it is not trained with exactly the same methodology.

1. There is no re-lighting data augmentation.
2. The non-zero biases are initialized to 0.1 instead of 1, since initialization to 1 resulted in flat training loss.

The bundled model is the training snapshot from iteration 360,000. The best observed model validation was

- iteration 358,000
- validation accuracy 57.258%
- loss 1.83948