Major changes to the Xconq interface code

[Hans Ronne <hronne at telia dot com>]

I have just checked in some major changes to the interface code. Wrapping
of x has been restricted to the kernel where accessor macros for the area
layers now always wrap x. Hopefully, this will eliminate both existing and
future wrapping bugs in the interfaces. Wrapping bugs have been among the
most frequently reported bugs on this list, and I therefore decided to try
to eliminate this problem once and for all.

As always when there are major changes, unexpected bugs may have sneaked
in, even if I have tested the new code extensively. Bug reports are welcome.

Hans

P.S. This fixes the two tcltk wrapping bugs reported recently by Lincoln
Peters, but there are still other dateline problems in the tcltk interface
that are not due to wrapping bugs.