Node.js agent v8.1.0

Notes

• Added necessary instrumentation to support v4 of mongodb.

  • Explicitly enabled APM for mongodb instrumentation(client.monitorCommands = true)

• Fixed issue where Promise based pg.Client.query timings were always in sub-millisecond range.

• Fixed bug where API.shutdown would not harvest or keep process active effectively after an agent restart.

  The agent will now correctly update its state to 'started' after a reconnect has completed.

• Added an eslint rule to verify every file includes the copyright statement.

• Fixed the homepage field in package.json to use https in the link to the github repo. Thank you @pzrq for the contribution.