[feature-request] Add support for space and comma separated strings parameters

Hi,
First of all, thanks for doing this, it helps bridging the gap with apis not available in C/C++.

I'm trying to pass a list of strings to a go plugin and at the moment it seems only a string can be passed.

One way to do it and this is what I do at the moment is to parse the space separated string into an array in my plugin but I'm not sure on how to integrate it "properly" in the lib. Could you give some guidelines on how to do it properly? I could make a PR then.

Thanks!