[tex4ht] htfgen testing

[Karl Berry]

> https://github.com/michal-h21/htfgen

Wow.  Just a few general thoughts from reading the README ...

- inevitably it will take plenty of non-automated info to get the output
right.  So if the tools had a way to incorporate manually-created
overrides, that seems like it could be helpful.  I'd expect there would
be overlap between fonts, not to mention rerunning in the event of new
releases, etc.

- it's such a big job that I wonder if it would be worthwhile to set up
some kind of project infrastructure -- e.g., an
(automatically-generated) list of fonts, the helper files, the output
files, the status, maybe who's working on it if Nasser or others can
help, etc.  Easy to imagine a web interface to make contributing easier,
even, if it seems worth it.

- regarding afm files, I'm somewhat doubtful that there are many
fonts with afm's but not enc's.  It should be pretty easy to check that
before going to the trouble of writing any code to check with afm's.

- it doesn't really matter unless we want to start distributing this,
but "lsenc" seems a bit generic.  Most encodings have nothing to do with
TeX (audio, video, etc.).  "lstexenc" would be preferable if it goes
public.

thanks,
karl