Fix Memory Leak

[Pilot-Marc]

Background

POIViewController was being retained in memory, causing the app's memory footprint to grow each time the POIViewController page was loaded.

• Three NSTimer calls were modified to use weak references to self.
• Two NSNotification callbacks were modified to use weak references to self.

Breaking Changes

iOS 9 and iOS 10 installations could see a run-time assert, but I don't think there's any way to get to the asserted routine in this circumstance. Regardless, the framework is about to lose iOS 9 and iOS 10 support anyway.

Meta

• Tied to Version Release(s): N/A.

PR Checklist

• CI runs clean?
• Appropriate label has been added to this PR (i.e., Bug, Enhancement, etc.).
• Documentation has been added to all open, and public scoped methods and properties.
• Changelog has been updated
• Tests have have been added to all new features. (not a requirement, but helpful)
• Image/GIFs have been added for all UI related changed.

Screenshots

Before Screenshot - Showing three invocations of POIViewController:

After Screenshot - Showing three invocations of POIViewController: