This is what similar types in libstd do (`CStr::to_str`, `OsStr::to_str`, `Path::to_str`).
All lua types should now be at least somewhat usable from rust, if incompletely so. Any lua value should be readable in Rust as a LuaValue, pop_value should never panic except in internal logic errors.
There is no longer any protection in passing LuaValue between independent states, it is being re-added
Jonas Schievink