Update to 2.2 snippet and API
Fix specs checking for Mixpanel script presence
Update README.md
added unset
added test
Bypass the middleware on individual requests by calling Mixpanel::Middleware.skip_this_request

Updated README to document its usage
update Readme and Changelog
update Readme, Changelog bump version

* by mistake a previous PR bumped version with the number
that we are releasing now.
support register_once
Add method to delete user from mixpanel

mixpanel.delete {distinct_id}
Changed gem source to https variant
Update changelog
bump version