Function: htmlfontify-copy-and-link-dir

Trawl SRCDIR and write fontified-and-hyperlinked output in DSTDIR.
F-EXT and L-EXT specify values for `hfy-extn' and `hfy-link-extn'.

You may also want to set `hfy-page-header' and `hfy-page-footer'.

(fn SRCDIR DSTDIR &optional F-EXT L-EXT)