Useful Dll for Inno Setup users

[peterf1999]

DiskVolumeInfo function replaced by:

const
  TF_InBytes = 1;
  TF_InKiloBytes = 2;
  TF_InMegaBytes = 4;
  TF_InGigaBytes = 8;

function GetDiskVolumeName(const RootDir: PAnsichar):PAnsichar; external 'GetDiskVolumeName@files:Isab.dll stdcall delayload';
function GetFileSystemName(const RootDir: PAnsichar):PAnsichar; external 'GetFileSystemName@files:Isab.dll stdcall delayload';
function GetVolumeFreeSpace(const RootDir: PAnsichar; const OutSizeType: Byte): Double; external 'GetVolumeFreeSpace@files:Isab.dll stdcall delayload';
function GetVolumeSize(const RootDir: PAnsichar; const OutSizeType: Byte): Double; external 'GetVolumeSize@files:Isab.dll stdcall delayload';