* lsdb.el (lsdb-interesting-header-alist): Add setting for Face: header.

* lsdb.el (lsdb-interesting-header-alist): Add setting for Face: header.
(lsdb-entry-type-alist): Add setting for 'face entry.
(lsdb-face-image-type): New user option.
(lsdb-face-command-alist): New user option.
(lsdb-insert-face-function): New user option.
(lsdb-print-record-hook): Add setting for lsdb-expose-face.
(lsdb-update-record): Don't modify 'net entry if canonical address
is not specified.
(lsdb-face-cache): New variable.
(lsdb-face-available-image-type): New function.
(lsdb-expose-face): New function.
(lsdb-insert-face-image): New function.
(lsdb-insert-face-asynchronously): New function.