Version 3.0.0

• Feature: Added official support for Node 8.x
• Feature: Added official support for Node 7.x
• Feature: Added support for is_test in submitHam and submitSpam
• Feature: Added test suite for the client promise API
• Feature: Requests to Akismet now default to HTTPS
• Feature: Added protocol option to the constructor
• Patch: Updated superagent to 3.0.0
• Patch: Updated nock to 9.0.6
• Patch: Updated chai to 4.0.1
• Patch: Updated mocha to 3.4.1
• Patch: Removed dependency on setimmediate
• Breaking: Removed support for Node 0.8. Node 0.8 reached end-of-life a
  very long time ago, you should upgrade if you are still using it.