Resolve #1298

* use serial.load in CIFAR10._unpickle
* remove "scripts/tutorials/grbm_smd/make_dataset.py" from pep8 whitelist
* refine serial.load for interoparability between Python 2 and 3
* remove N and np, aliases of numpy
We try to encourage all library code to use serial.load when at all possible. Having this function will encourage people to call this instead of serial.load.

What happens if you're not in PY3 and you pass encoding='latin-1' to cPickle.load? If nothing bad happens, just change all the cPickle.load calls in serial.load.

If that does something bad, then just move pickle_load to serial._pickle_load.