- Added information on the types of volumes returned by 
  TWinNTSystem::GetVolumes():
  - Type of drive: local, removable, network, CD/DVD
  - File System: NTFS, AFS, NFS
- Adapted TGFSCombobox and TGFileBrowser accordingly to these new info
- Added two new icons to represent Network drives on Windows


git-svn-id: http://root.cern.ch/svn/root/trunk@23664 27541ba8-7e3a-0410-8455-c3a389f83636