Vob linebreaking

[Tuomas Lukka <lukka@xxxxxxxxxx>]

Finally, found a satisfactory solution: at first, simply insist that all
spaces are between vobs. That way, we can just use TeX's glue model
for the boxes. Hyphenation can be done later and as in TeX (IIRC), only
after trying to break with the spaces. That way, there's no need for the
endIsBreak etc. stuff.

Only difficult situation is where the spans' breaks go like

	foo bar| |baz

or even worse,

	foo.| | |bar

But I'm sure we'll find a way to handle these.

	Tuomas