wrong wordwrap behaviour

[gale daedalus dra hmg gb]

The text widget now does word wrap on word boundaries, which is good, but the
behaviour of the function gtk_text_set_word_wrap is, I would argue, wrong.

This function toggles between the text widget wrapping whole words and breaking
words across lines. The Motif, and IMO correct, behaviour is to *always* wrap words
on word boundaries and for wordwrap itself to be toggled - this used to be the
behaviour under GTK aswell.

The current behaviour results, for example, in the text example in testgtk.c having a
useless horizontal scrollbar.

Thanks

Tony