Use Sliding Volume Switch on Modded Arcade1UP Marvel Super Hero Cabinet

Credit: urvaius for the "arcade1up_powerandvolume" at https://github.com/urvaius/arcade1up_... The original instructions can be found at the above link. The original code worked, but would error out if the volume went outside the range of 0-100. I corrected the code to contain the volume within the 0-100 limits. The corrected code can be found at https://www.dropbox.com/s/p5oiluujfv0... These Instructions can be found at https://www.dropbox.com/s/ta7n0rrhyn1... This installation is for new Arcade1Up cabinets that have a sliding volume control like the Marvel Super Heroes cabinet and not the generation 1 cabinet with the toggle switch. Note that volume cannot be changed during the boot up Splash screen video playback or while in EmulationStation or Attract mode.