Set cookie in response and return version in endpoint data.

By setting the cookie in the response, the client is able to tell when
the export(for each type) has finished. Also, by returning the version
as part of the endpoint data. The client will be able to determine
whether they can rely on the cookie being set or if they need to work
without the cookie.
Update API_VERSION with separator and micro, use in exporter endpoint
Merge pull request #40 from cbmi/enable-export-progress

Set cookie in response and return version in endpoint data