[Coco] Accessing HD image under MESS

[arikboke at yahoo.com]

Thanks to Tim for his links and Robert for his EDTASM primer!  As far as
Portal-9 is concerned, it seemed to choke on the code for Black Sanctum.  All
the ASM files were stated to be "skipped".  Perhaps the demo version will not
assemble things properly or perhaps there is line number limit to it.  In any
case, as my primary goal was to get the original EDTASM working on MESS, I'll
give it another whir.

--David