Move ODCIL to first byte per draft-17

Travis: add cppcheck

Don't suppport use --project=compile_commands.json
add script to build from source

Draft17=long header fix

update key rotation vector test

.travis(.yml): Update (matrix) travis build

Adding test vector for draft-17 initial encryption

Check addresses of probes and responses

Update Travis to Xenial

split clang and clang analyzer (scan-build) build
use matrix (with name !) to different build

and now clang(-7) is install by default

fix path to scan-build (ccc-analyer)

Xenial is now available with Travis CI
https://blog.travis-ci.com/2018-11-08-xenial-release

Implementation of draft-17