Beeline for Node.js v1.2.0, with better concurrent async support

Honeycomb's Beeline for Node.js version 1.2.0 has been published to NPM. This release features improved support for concurrent asynchronous operations. This support is exposed through the API as startAsyncSpan, which the built-in instrumentation has been updated to use.

Check the repo's docs/API.md for more information and example usage.