* wl/wl-vars.el:

* wl/wl-vars.el:
New variable (wl-message-truncate-lines, wl-draft-truncate-lines).

* wl/wl-message.el, wl/wl-draft.el:
Use it to set truncate-lines.

* samples/en/dot.wl, samples/ja/dot.wl
Add truncation settings.

* doc/wl-ja.texi, doc/wl.texi: Update.
NOTE: We should reconsider the place of wl-{folder|summary}-use-frame
in info.