Add support for more standard containers

[haudren]

Hello,

I recently needed to wrap triplets. Unfortunately, it looks like Pybindgen does not support either of:

• std::pair
• std::tuple
• std::array (I ended up using an std::vector)

I think that std::pair/std::tuple could be easily mapped to python tuples, and array to a python list. What are your thoughts on this ?