BWidget path problems fixed

[Hans Ronne]

>I put modified game files into ~/.xconq/lib/ja and run xconq with -L
>~/.xconq/lib/ja.
>It don't work with the current tkconq.tcl.
>
>In Unix, the line seems to work.
>   lappend auto_path [file join [file dirname [info script]] BWidget]

This works for me too (also when XCONQLIB is undefined) so I have checked
it in. Being free to use -L to set the default game directory to anywhere
is an advantage, even if I rarely use this option myself.

Hans

P.S. Any progress with the tree code? That was after all the reason why we
added BWidget.