#185 pagelist not scrolled back after geom change

[Stefan Ulrich]

Usually, the current page in the pagelist is scrolled
back into the visible area when switching pages. Under
certain conditions this doesn't work in Xaw and Motif:

Motif:
- when current page is at bottom and window is made smaller
via the window manager, the current page is not
scrolled back
into the visible area. When hitting RET for next
page, it is
brought back into visible.

Xaw:
- above works, but when window is made larger, there's
a hack
to fit the pagelist geometry that removes and
re-creates the
pagelist widgets. In that case, the old scroll value
is forgotten
and the current page will get out of the scrolled
area (it's
brought back when scrolling a bit, then hitting RET
for next
page).