Add -Wextra (with -Wno-unused-parameter) to unix builds in addition to
-Wall -Werror.
This can successfully build everything in Sai without warnings / errors.
- 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