(lsdb-x-face-image-type): New user option.

(lsdb-x-face-image-type): New user option.
(lsdb-insert-x-face-asynchronously): Respect lsdb-x-face-image-type.
(lsdb-mode-quit-window): Don't pass an argument to bury-buffer when we are already on the selected-window.
(lsdb-mew-insinuate): Advise mew-summary-visit-folder and mew-summary-switch-to-folder to hide *LSDB* buffer.
(lsdb-mew-update-record): Rewrite.
Autoload mew-xinfo-get-decode-err and mew-xinfo-get-action when compiling.
From Hideyuki SHIRAI <shirai@meadowy.org>