Correcting Un-PEP263 encoding definition

[alvations]

Un-PEP263-like style of encoding definitions should be corrected. The python script's encoding should be magically declared in the 1st/2nd line otherwise it'll not be useful and be treated as a normal comment.

Maybe it should follow how TF's style where the encoding definition comes the license/copyrights, e.g. https://github.com/tensorflow/tensorflow/blob/master/tensorflow/tensorboard/lib/python/http_util_test.py

For details, see http://stackoverflow.com/q/42777847/610569

[dennybritz]

Oh, this is good, I had no idea. Will fix :)