More WIP: softlist for mc1502 software

I had to hack wd_fdc.c, not sure how to do this cleaner. The reset routine (INT 13H AH=00) fails otherwise -- it waits for S_NRDY to clear and it never does.

How to use: press Enter twice after POST completes, at the '-' prompt enter '@'.

'ots' is a bad dump -- apparently the disk had 82 or more tracks, only 80 are dumped. It shows the logo, though.

'sfdos' is a good dump (it boots in ec1841), but doesn't boot here (fails to read 4 sectors starting at chs 0:1:6).