NTFS write support NTFS_RW

This enables the partial, but safe, write support in the NTFS driver.

The only supported operation is overwriting existing files, without
changing the file length.  No file or directory creation, deletion or
renaming is possible.  Note only non-resident files can be written to
so you may find that some very small files (<500 bytes or so) cannot
be written to.

While we cannot guarantee that it will not damage any data, we have
so far not received a single report where the driver would have
damaged someones data so we assume it is perfectly safe to use.

Note:  While write support is safe in this version (a rewrite from
scratch of the NTFS support), it should be noted that the old NTFS
write support, included in Linux 2.5.10 and before (since 1997),
is not safe.

This is currently useful with TopologiLinux.  TopologiLinux is run
on top of any DOS/Microsoft Windows system without partitioning your
hard disk.  Unlike other Linux distributions TopologiLinux does not
need its own partition.  For more information see
<http://topologi-linux.sourceforge.net/>

It is perfectly safe to say N here.