fix for supplied argument on start

[MrsDelish]

Added a check to see if bat file was started with a supplied argument (number) so it can be started from a startup file on boot.

Guide: Edit: bbt-multiminerv5.7-autostart.bat set option (number) you want to autostart. Press: win + R Type: shell:startup Press: enter Create a shortcut from "bbt-multiminerv5.7-autostart.bat" to startup folder

Now bbt-multiminer should start with the set option on each reboot.