Most of the network-facing facilities have been copied to the socket and
openssl streams. No code now uses these functions directly anymore, so
we can now remove them.
This unfortunately isn't as stackable as could be possible, as it
hard-codes the socket stream. This is because the method of using a
custom openssl BIO is not clear, and we do not need this for now. We can
still bring this in if and as we need it.
We currently have gitno for talking over TCP, but this needs to know
about both plaintext and OpenSSL connections and the code has gotten
somewhat messy with ifdefs determining which version of the function
should be called.
In order to clean this up and abstract away the details of sending over
the different types of streams, we can instead use an interface and
stack stream implementations.
We may not be able to use the stackability with all streams, but we
are definitely be able to use the abstraction which is currently spread
between different bits of gitno.
