session.new is always true

[armonge]

The Session object of every request always has the new attribute set to true. This is a hardcoded value in https://github.com/BrianMacIntosh/alexa-skill-test-framework/blob/master/index.js#L400

Expected behavior would be to only have this be true for the first request in the sequence. The reference in https://developer.amazon.com/public/solutions/alexa/alexa-skills-kit/docs/alexa-skills-kit-interface-reference states that new "Returns true for a new session or false for an existing session."