BWidget install problems on unix fixed

[Hans Ronne]

I have now updated the Makefiles so that BWidget installs with the other
xconq stuff on unix. Hopefully, this will fix some of the recent problems,
which all seem to involve installed versions and not build versions.

Please note that I have also changed the install location of tkconq.tcl and
imfapp.tcl from whatever/xconq to the new directory whatever/xconq/tcltk.
It is therefore extra important that you delete the old installed files
before running make install, or you may end up executing the old stale
tkconq.tcl.

Hans