Updated DOS drivers

Jack Ellis has updated his DOS drivers. This update fixes old 386 errata and ATAPI flag bugs for UHDD, as well as handling of LBA48 drives above 128 GB size. The only updates are for UHDD, all other files are the same. You can download the new "February 15, 2019" version at ibiblio.
Update: Jack made a small update to comments in the sources, and the readme. I have posted that version as February 15, 2019(A) in the same directory: drivers-2019-02-15a.zip