Moved R/W data in the BIOS to 0xd000, and use indirect jumps/calls instead
of patched jumps/calls, so that the 0xe000-0xffff area is read-only.
Added IBM signature at 0xe000.


git-svn-id: https://dosemu.svn.sourceforge.net/svnroot/dosemu/trunk@1329 7758b857-130e-0410-ab9c-d8735a528d18