add $FreeBSD.
get copyright in sync with FreeBSD recommendation.
remove obsolete stuff resuling from pcvt kernel part cleanup
(caution: this depends in part on modifications to pcvt_ioctl.h,
commit will follow shortly).
add new option "-n" to ispcvt to get number of compiled-in
virtual screens.
in here that just made it a heck of a lot more confusing to maintain.
Somebody like Joerg can reality-check this at some point, when they have more
time. For now, it works.
