Uses shell functions to correctly get the My Documents and Desktop folders and then add them to the fsmenu, right below the drive letters.

Notes:
- For some weird reason, shlobj.h needs to be included before BLI_winstuff.h. Maybe some not nice things going on there.

- Needs to add shell32.lib as a linking target. The patch does it for MSVC 6.0 projectfiles, but other build engines would have to be fixed too.

Assigning to Aphex, our Win platform maintainer.