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~~ to be continued...
- fix #525 by scaling data to [0, 255], doing mean subtraction, and then input scaling
These should be `is not None`.