RE: fuzzing SDFs

[armin]

>> I did check it out and I think simply adding the new render modes to 
>> the render mode list should be sufficient.  [...]
>
> Looks good!  Please submit a Pull Request that Armin (and others) can
review.

Agreed! :)

> Note that a major problem will probably be timeouts: Right now it can
happen
> that the fuzzing code wants to render too much glyphs in one run.  Since
the
> SDF mode is really slow I guess we will see much more of such issues,
which
> can become a hassle.
>
> Armin, do you have ideas how this could be improved and/or avoided in
> general?

I think generally there are two options:

- We do have a few screws at this point to steer how many glyphs we're
looking at in a single fuzzer run.  We could either use one of the existing
ones or, if they are to coarse, we could introduce new screws that
specifically target the SDF mode.

- Alternatively SDF could get it's very own fuzzer.  We've already done this
to separate rendering from utility access;  we _could_ look into further
separating fuzzing rendering from fuzzing SDF rendering.  Although, that
would be quite a lot of work.