[tex4ht] Tex4ht and XeTeX and Unicode

[Karl Berry]

    There are several scripts available for XeLaTeX in the TeX4ht
    bundle, Dominik:

These (among many others of Eitan's endless and ever-expanding list of
scripts) are not installed by default in TL, as of last year.  Probably
we should reinstate htexelatex, but I am loath to do the others, since
it's supposed to be straightforward to use the generic mk4ht frontend
instead.

(Though I don't believe they are 100% equivalent right now; remember we
couldn't figure out a way to pass tex args through mk4ht, though they
can be passed to, say, htlatex ... sigh.  Another thing for the endless
and ever-expanding list of things to do.)