HTTP: ignore duplicate writeHead calls after headers are sent. Fixes #71
Run all tests, not just the writeHead() one
Merge pull request #76 from snorp/run-all-tests

Tests - Run all tests, not just the writeHead() one
Update version number and references

Don't update HISTORY.md yet, as the new draft isn't actually out!
Update HISTORY
Merge pull request #79 from todesschaf/wip/draft14

Update to latest version of node-http2-protocol