Rendering NotificationDetails when the app launches from a PushNote

#### Goal:

The objective of this Pull Request is to push the Notification Details, when the app is launched from a Push Notification.


#### Scenario A: Notification is available

This is the simplest case. We just go ahead and push, with no animation, the notification details.

#### Scenario B: Notification wasn't sync'ed

If the note is not already available, we keep a reference to its *simperiumKey*, and we capture a timestamp representing the ""tap instant"".

Whenever the target Notification is loaded, we check the time elapsed between the "Open app via Push Notification" event, and "Simperium sync'ed the note". If a given threshold hasn't elapsed (2 secs), we go ahead and push the details. Otherwise, the user is just left in the NotificationsViewController.

#### Notes:

This Pull Request depends on the fixes introduced in #2179. (The corresponding branch has already been merged in here).

Fixes #1767