Sets the number of minutes before the screen blanks out to prevent
screen burn. Since this is not a resident program, screen blanking is
only active while the menu system is active. Setting BlankTime to 0
prevents screen blanking.
Example:
BlankTime = 10 ;set to 10 minutes
BlankTime = 0 ;disables screen blanking
Writeln BlankTime " Minutes of inactivity will cause screen blanking."
