6502: typo fix
dragon: fix off by one in devfd
trs80: further work on the hd driver

Still needs a floppy boot block to begin testing
zx128: Add support for the sinclair Microdrive

Read only for the moment, but tested with the boot loader path and seems to
be doing the right thing. Something is buggy in the checksum logic either
of the mdv maker or the reader, not sure which yet.

Headers and blocks are correctly fetched, data blocks are split from the header
as they arrive to avoid double buffering.

The interface 1 ROM is not used at all (so we can use this from a cartridge
to load the rest of the OS)
zx128: put devices in the same order as other platforms, hook microdrive

We'll need some CONFIG options to select between Microdrive, floppy etc as
I don't think the average Russian Spectrum/Clone came with a Microdrive !
zx128: link and crt0

Call the microdrive init functions
Do the initializer copy (makes no odds if disk loading, matters if ROM)
Shuffle things so that the kernel is at 0x0000->0x3FFF and 0xC000+. The
common, video and other bits then live between 5B and 9F. That leaves us
with A0-BF free plus the C0-FF of the other banks, so we can run somewhat
bigger apps. Not ideal but SDCC hacking is going to be needed to do better
plus teach fuse to emulate banked cartridges.

Memory map open to discussion anyway.

BUG: right now the mdv loader doesn't load 0xFE00-0xFFFF but needs to, need
to move the boot stack first.
Makefile: add run for bintomdv
bintomdv: convert the binary into microdrive cartridge and interface 2 ROM
trs80: Fix off by one in floppy code