Improve and polish pycaffe

- fix input preprocessing configuration in 3cac223 picking up on #733
- update examples' outputs given correct preprocessing 9d7346b, always include caffe pythonpath 45d74bd, and reword classification + time on a gtx 770 fc01ee6
- add console output with human-readable labels and a grayscale flag to classify.py courtesy of @petewarden's #735
- fix #525 by scaling data to [0, 255], doing mean subtraction, and then input scaling
Is this expansion a substantial optimization? I don't feel too bad about rewriting the preprocessing list comprehensions as loops, since they already have internal logic, but here it's just direct list-to-array; I can't read this code without wondering why it was done this way.

Here the speed difference should be smaller by a factor of the batch size. If this is still important, perhaps we could put this logic in a helper function that includes an explanation for its existence?