MS-DOS Player

What's New:

      • Improve MGetVdmPointer and VdmMapFlat to consider mode argument
      • Add dummy functions for memory hook/allocation
      • Support Virtual Device Driver (thanks Mr. cracyc)
      • Improve INT 21H, AH=30H to return 5.00 as DOS version
      • Improve INT 21H, AH=3306H to return 5.50 as true DOS version