Indexing suite

Hello,
There is this [repo](https://github.com/JohnReid/boost-indexing-suite.git) where some users have added more std containers via the index suite. like std::multi_map and others.
What would be involved in getting this included in the master boost.python?

Also, where do users ask questions nowadays. [This](https://www.boost.org/community/groups.html) refers to [Python C++-sig](http://www.python.org/community/sigs/current/c++-sig/) that doesn't exist anymore

首先检查外部 boost-indexing-suite 仓库，并将其中新增的 std 容器与当前的 Boost.Python master indexing suite 进行比较。确定纳入范围和兼容性要求，然后根据链接的社区指南核实当前用于用户提问的渠道；当两个请求都有已决定且记录在案的处理路径时，即表示完成。

由索引模型根据 Issue 内容生成。