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
Not sure what `dtype=np.float32` is doing here... won't it just be promoted to `float64` anyway? E.g.,

```python
$ ipython --no-banner

In [1]: import numpy as np

In [2]: (np.array(5) / np.array(4, dtype=np.float32)).dtype
Out[2]: dtype('float64')
```