[Feature Request] Private option.

[huxuan]

Currently, the template does not work very well with private repositories:

1. There is Private :: Do Not Upload that should apply to the package to avoid accidental uploads to the public PyPI.

   To prevent a package from being uploaded to PyPI, use the special "Private :: Do Not Upload" classifier. PyPI will always reject packages with classifiers beginning with "Private ::".

   Ref: https://pypi.org/classifiers/

2. Some badges in the README will be invalid for private repositories.

[huxuan]

@msclock Any comments on this? I would like to implement it as the next pull request.

[msclock]

@msclock Any comments on this? I would like to implement it as the next pull request.

I'm ok with it. Actually, I think this essentially cuts off the way to upload packages.

[huxuan]

Remove from milestion v0.1.0 since it is not a required feature for the first release.