Native Stats

### Native stats

Note that there is no way to drill into the fine detail that the webview provided. The Android version of the app is the same. Adding a button in the `rightBarButtonItem` to link to the original website via Safari might be a good idea, if users find they need to see more.

##### Notable Features
1. Click/Referrer groups dropdown to show the outbound/inbound links
2. Graph shows 7 or 12 (iPad) points of interest for views/visitors over time, over 'days', 'weeks', 'months'. (more could be added later, with a scrollview)
3. Integration for stats notifications #1051 *I've assumed the notification type == `traffic_surge` -- I'm not sure if there are others.
4. Jetpack support as with the original web view (includes modification of Jetpack login handling. rel #935)

##### Other notes
1. Localisations need to be done for the strings (assuming this is done at build release time)
2. There are no Mixpanel stats recorded on this screen yet

##### Very Long Screenshot
http://codeforcake.files.wordpress.com/2014/01/stats_long.jpeg

Fixes #986