Added first steps toward tracking analytics for jetpack.
Adding a way to tell if a blog isn't connected to Jetpack.
Adding WPAnalytics calls for jetpack tracking.
Changed mixpanel stat instructions to allow multiple super properties.
Adding "dotcom_user" and "jetpack_user" super properties.
Removing property from WPAnalyticsStatSelectedInstallJetpack.

I incorrectly added a source to this property without realizing that
it can come from multiple sources.
Renaming one of the jetpack related stats.
Adding missing super property flags to jetpack sign in from stats.
Adjusting superPropertiesToFlag to return a copy of the array.
Clarifying comment for Blog property hasJetpackAndIsConnectedToWPCom.
Merge pull request #1574 from wordpress-mobile/issue/1573-add-jetpack-analytics

Add Jetpack Analytics