Readme - concurrency.

[andrewchambers]

Could you write a readme heading describing how go routines interact with gopher-lua, and what is/isn't thread safe.

[yuin]

In short, the LState is not goroutine-safe. I would recommend to use one LState per goroutine and communicate between goroutines by using channels.

BTW, I am planning to introduce some channel supports into the GopherLua.
I will write a readme about goroutines when the implementation is completed.

[andrewchambers]

Thanks for the info.