Add file rename to OS functions

[angus]

It's extremely handy when you're using file-based communication. And saves one thread reading a file that another hasn't finished writing. 

[silent]

Hi Angus,

Not sure, but rename() method is already available under File System functions: https://developer.unigine.com/en/docs/2.5/api/library/filesystem/functions.filesystem#rename_string_string_int

Is that what you are looking for?

Thanks!

[angus]

Thanks, Silent. I must have missed it.