The Infrastructure "system" command, or "iSys".    Perform the supplied command, capturing it's output characters.    The command is made by expanding "fmt" using the variable arguments "...".    The argument "to" is timeout in milliseconds.    The argument outMax is the size fo the output buffer (expected output from the command).    Return the output string to the caller, else NULL.    Note, the caller must free the returned string if not NULL.