Package license file

[jakirkham]

Please include the license file in the PyPI releases. This helps downstream distributors who need to pass the license file along to their users. Thanks.

[jart]

@jakirkham TensorBoard on PyPi now has license metadata, as of the TensorBoard 0.1.8 issued today. There were a couple other issues I noticed with the pip package, which have also been addressed. You should be good to go now!