add function for saving predictions

Add the function of saving prediction to cPickle files. Multiview and multiple batch for testing is supported.

Usage: python shownet.py --load-file=your-model-path --show-preds=probs --save-preds=/home/qiang/Documents/image-net --multiview-test=1

Format: for each batch, a cPickle file will be created, which includes a numpy array of dimension [num_image x num_view, num_class]