Make eww rendering default to `window-width' again

* lisp/gnus/mm-decode.el (mm-shr): Bind `shr-width' to `fill-column'
so that lines don't get overlong when responding.

* lisp/net/eww.el (eww-mode): Truncate overlong lines for prettier
display when resizing.

* lisp/net/shr.el (shr-width): Default to using the window width when
rendering.
lisp/gnus/gnus-cloud.el: Start collecting a newsrc
international/mule.el (make-translation-table-from-alist): Accept nil or zero-length vector for FROM and TO.
Merge branch 'master' of git.sv.gnu.org:/srv/git/emacs.