Indexing suite

[finjulhich]

Hello,
There is this repo 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 refers to Python C++-sig that doesn't exist anymore

[finjulhich]

@raoul Gough was involved in the initial code I believe