Remove some skeletons in the closet

Not to dance around the issue too much: when I started the Cryptosphere
I was naive... very naive. I guess this code was part of me trying to
design an encrypted transport protocol without the slightest idea what I
was doing.

I've been studying cryptography quite a bit since I originally wrote
this, and now I am thoroughly convinced: designing an encrypted
transport protocol is one of the hardest cryptosystems a person can
possibly design. I've written up my thoughts about what encrypted
transport protocols the Cryptosphere should investigate here:

https://github.com/cryptosphere/cryptosphere/wiki/Protocol

People are looking at this ancient code that I have no intention to use
ever, but it's still here, and I guess that's a cause for concern. Here
was one of the issues:

https://github.com/cryptosphere/cryptosphere/issues/4

Going forward the Cryptosphere will be built on high-level authenticated
cryptosystems designed by professional cryptographers. The present plan
is to use Dan J. Bernstein's designs, including NaCl's secret_box and
the CurveCP encrypted transport protocol. If CurveCP doesn't pan out,
the Cryptosphere will use DTLS+LEDBAT.