[Groff] Widow control

[Larry Kollar]

>If you compile groff with -DWIDOW_CONTROL, you'll get
>two new requests `wdc'(activate widow control) and `fpl'
>(flush pending lines) which prohibits widows.

I gave it a shot last night on my home & work systems.
On both systems, enabling wdc (on the same input file)
prevented widow lines at the top of the page all right,
but .ne seemed to have no effect on four- and five-line
paragraphs that straddled the page. Most of them would
print a single line at the bottom of the page & send
the rest to the next page.  Using .ne 2, .ne 3, and
even .ne 4 made no difference.

Just testing. This was with 1.16.1; I'll try the snapshot
next.

        Larry (testing, one, two, three... dang)