Integrate code from John P. Wittkoski <jpw@netwizards.net> and

Integrate code from John P. Wittkoski <jpw@netwizards.net> and
Takashi Hamada <hamada@next.etron.kanazawa-it.ac.jp>.  This code
interfaces directly to the hardware to support the ADB on many
macs.  It is enabled by "options HWDIRECT" in the configuration
file.  At some point, this should probably become the default method
as interfacing to the ADB through the ROMs has been painful and sometimes
problematic.

This code should have functioning ADB support for:
	II series (II, SE/30, IIx, IIcx)
	IIsi series (IIsi, IIci, IIvx, IIvi)
	LC II, LC III
	Performa 400, 405, 430, 460, 465, 467, 600
	Classic II, Color Classic, Color Classic II
	PB 5XX series
	Duo series
	PB 140,145,145b,160,(160c?),165,165c,170,180,180c
	Quadra 700,900,950
There is an off-chance that it will work on:
	PB 150, PB 190
	Quadra/Centris 605,610,630,650,660AV,800,840AV
	LC 475,550,575,630
	Performa 475,476,575,577,578,630
Note that functioning ADB support does not mean that everything else
will work.  I obviously do not own all of the above machines (does
anyone?  ;-)...  Any reports are welcome.

Many thanks to John Wittkoski and Takashi Hamada!