<<PATCH>> Added shell32.dll functions to browse for unix directory; altered winecfg to use it to select the root directory of a virtual drive

[Robert van Herk]

Changes:

Added functionality to browse for a UNIX folder.
This is done by making two new funtions in dlls/shell32/brsfolder.c, namely
        wine_shell_browse_for_UNIX_directoryA
        wine_shell_browse_for_UNIX_directoryW
These functions are exported in shlobj.h.

The original code that allowed just for picking a Windows folder, was 
split up.
It was to be found in brsfolder.c, but I split this in:
brsfolder.c
brsfolder.h
brsfolder_windows.c
brsfolder_windows.h
brsfolder_unix.c
brsfolder_unix.h
unixTools.c
unixTools.h,
Otherwise I found the code to be incomprehendible.

Furthermore, winecfg now uses the wine_shell_browse_for_UNIX_directoryA
to let the user pick a UNIX directory as root for his virtual drive 
mappings.

Regards,
Robert van Herk