Setuptools < 36.8.0 no longer supported by PyPI

Due to the [deprecation of non-SNI support on PyPI](https://github.com/pypa/pypi-support/issues/978) buildout bootstrapping is currently broken.

The fix requires obtaining a patched setuptools for this as zc.buildout can't work with newer versions; we can backport [the original change](https://github.com/pypa/setuptools/pull/1190/files) and have bootstrap work from the patched version.

Until someone gets round to this, however, this project is not going to be usable by anyone not already bootstrapped.

首先阅读链接的 PyPI 支持 issue 和原始的 setuptools pull request 1190，然后跟踪 issue 中描述的 buildout 引导过程。当使用打过补丁的 setuptools 版本时，全新的 bootstrap 能够在 PyPI 上正常工作，同时保持与 zc.buildout 的兼容性，即表示完成。

由索引模型根据 Issue 内容生成。