1) update the logos to svg
2) add svg icon for strict security policy where used
3) define new vhost option flag to enforce sending CSP headers
with the result code
4) add vhost option flag to minimal examples to
enforce sending CSP where applicable
5) Go through all the affecting examples confirming they
still work
6) add LWS_RECOMMENDED_MIN_HEADER_SPACE constant (currently
2048) to clarify when we need a buffer to hold headers...
with CSP the headers have become potentially a lot
larger.
Several new ops are planned for tls... so better to bite the bullet and
clean it out to the same level as roles + event-libs first.
Also adds a new travis target "mbedtls" and all the tests except
autobahn against mbedtls build.
This converts several of the selftests to return a status in their exit code
about whether they 'worked'.
A small bash script framework is added, with a selftest.sh in the mininmal
example dirs that support it, and a ./minimal-examples/selftests.sh script
that can be run from the build dir with no args that discovers and runs all
the selftest.sh scripts underneath.
That is also integrated into travis and the enabled tests must pass now for
travis to pass. Travis does not have a modern libuv so it can't run a
couple of tests which are nulled out if it sees it's running in travis env.
