[Cooker] Update dosutils

[Hoyt]

Include the most recent rawritewin.exe.

Replace rawrite.exe with rawrite2.

Make text files in dosutils DOS text files with a .txt extension so they can
be easily read in DOS/Windows - this what people that typically use these
utilities are running at the time they are trying to use them. Same with the
README in /images since it gives the info for DOS-based installs - -and
change the name to something more informative.

Also include in /images a text file that explians how to create and use the
rescue disk.

Hoyt