[Cryptech Core] Questions regarding existing documentation

[Randy Bush]

> But I think we could (should) deprecate (delete) the doc/presentations
> and test/external_avalanche_entropy. The contents in these repos are
> pretty irrelevant and obsolete by now. I can probably do it but would
> appreciate an OK before doing so.

presentations should either be dumped or i should push a bunch of more
recent things to it.  do folk really care?

randy