[Dxbase] Update prefix database

[George Harlem W1EBI]

I can't remember whether I imported my updated country prefix database
from 2005 into 2006, but I see that a whole bunch of YTx prefixes are
being mapped into 9A, Z3 or S5 as primary prefixes.  Is the 2006 alias
map still showing this?  I guess I have to go through the entire
database and bring it up to date--again.  I know I did this in my copy
of 2005, but maybe the alias map was not updated for 2006...?

George W1EBI