feat: add refork

[mek-yt]

Hi,

I wanted to create a small GUI for Hugo, the server can be run with the Hugo function running an uncontrollable infinite loop, so with goroutine, parent can't kill children.
I found this library which allow me kill of the forked process but doesn't allow to fork again without recreating the function (restart the server). So I create a ReFork function using previous Function and rewriting Function.c with a new os.Cmd.

Do you think there is a better way ?

Thanks