Retire mcpp which was superseeded by tradcpp.

ok drahn@
lgtm natano@
link cpp.1 to tradcpp.1 now that mcpp is gone

ok drahn@
lgtm natano@
remove fdformat(1)

floppy disks have been obsolete for nearly a decade. we have no interest
in supporting them, so there's no point in having this code lying
around.

ok marco@ patrick@ natano@
remove ioctl_fd.h

it was only used by fdformat(1), which has been removed.

ok marco@ patrick@ natano@
remove sti(4)

although theoretically possible, the odds that we will ever run on a
platform with a hp-style text interface are pretty low, so unplug sti(4)
from the tree and remove it.

ok marco@ patrick@ natano@
remove dead files

these are mostly i386 drivers which were never enabled on amd64, and
that are unlikely to be found on anything remotely modern: pcmcia
controllers, old uarts and pc card drivers.

ok marco@ patrick@ natano@
zap man pages for previously removed drivers

ok marco@ patrick@ natano@
remove libexec/mcpp from include/Makefile

bad patrick. his employer, future wife and mother in law have been
notified.

his myspace account has been disabled.
Kill NULLVP; no need to explicitly cast void pointers in this century.

"feel free to kill it" pedro@
wip: Implement devfs.
Add mount_devfs.
devfs_readdir() bits; ugly but works (mostly)
rework
whoops
wip
wip
wip
wip
nullop is nullop
fix