This includes a minor SDK refactor as it move quite a few specialized
functions and facilities from core.h into system.h. There was a breaking point
for needing to frequently update core includes.
The new logger systemLog function allows a call site to bypass logging config
and write a line to the OS logger (aka syslog).
Distributed tests were failing every now and then because the test
plugin didn't implement retry's and the test server wasn't always
starting up fast enough. I fixed this by refactoring the tests to use
the real TLS plugin, which has retry logic. This required some mangling
of the configuration options, which should serve as a good reference as
well.
