Clone clones *public fields* in a structure.

CloneFallible clones *public fields* in a structure.

GetConfigDirectory will return where config and state files should be stored, either respecting `FLY_CONFIG_DIR` or defaulting to the user's home directory at `~/.fly`.

HasPipedStdin returns if stdin has piped input.

RandBytes generates random bytes of a given length See: https://stackoverflow.com/questions/35781197/generating-a-random-fixed-length-byte-array-in-go.

RandHex generates a random hex string of a given length*2.

RandString returns a string of n bytes, consisting of ASCII letters or numbers.