Correct a comment about payload layout and add detailed comments about
dsh handling at proxy.
Increase the post size so it shows up fragmentation issues at the proxy.
- Add low level system message distibution framework
- Add support for local Secure Streams to participate using _lws_smd streamtype
- Add apit test and minimal example
- Add SS proxy support for _lws_smd
See minimal-secure-streams-smd README.md