Fix support for node LTS versions

[jacobheun]

• Updates travis builds to be node LTS (6,8,10)
• Remove use of safe-buffer
• Update dependencies
• Fix linting for new version of standard
• NPNProtocols is no longer used by TLS, so use ALPNProtocols (test suite change only)
• Fix deprecated warnings

Changes in node 11.1.0

The build is currently breaking for node 11.1.0 as the params for onStreamRead have changed https://github.com/nodejs/node/blob/v11.1.0/lib/internal/stream_base_commons.js#L111. The handle-thing module will need to be updated to support that change.

Depends on

• [x] handle-thing#5
• [x] spdy-transport#61

[daviddias]

@jacobheun can you please update the package-lock.json with the new released versions of spdy-transport and handle-thing?

[jacobheun]

@diasdavid package lock has been updated. I also dropped stable from Travis to focus on the LTS versions. Once https://github.com/spdy-http2/handle-thing/issues/6 is resolved we can update Travis here as well.