So, I implemented the equivalent of PCVT_META_ESC for wscons.  I
haven't committed it yet but hope to be able to soon..

It turned out to require some fairly significant interface changes,
among them:

 - modifier bits needed to be made visible outside wskbd.c
 - modifier state needed to be passed to the wsdisplay_kbdinput and
emulator input routines.

I hope there isn't significant objection to this change.. it seems
fundamentally wrong to me that an emulation can't arrange to send
different character strings from its function keys based on the state
of modifier bits in an emulation-dependant way..

One thing I haven't found a good home for is the option bit that tells
the emulator whether or not to do the META->ESC prefix translation vs
set-8th-bit.  Right now, I have it as a compile-time option, but
that's clearly not the way to go.

					- Bill