Deregister notification observers and listeners before application termination

[fractalwrench]

Goal

Deregister any listeners or observers when the app is about to terminate, to prevent allocations from occurring during dealloc.

Changeset

• Update Podfiles for example apps to latest version
• Add an observer for termination notifications for each platform
• Remove all notification observers when a termination notification is received
• Stop watching connectivity changes when about to terminate
• Stop watching orientation/battery monitoring when about to terminate

Tests

Ran the iOS and macOS example apps and confirmed the stop method was invoked, and that no crashes were detected on exiting the application

Review

For the submitter, initial self-review:

• Commented on code changes inline explain the reasoning behind the approach
• Reviewed the test cases added for completeness and possible points for discussion
• A changelog entry was added for the goal of this pull request
• Check the scope of the changeset - is everything in the diff required for the pull request?
• This pull request is ready for:
  • Initial review of the intended approach, not yet feature complete
  • Structural review of the classes, functions, and properties modified
  • Final review

For the pull request reviewer(s), this changeset has been reviewed for:

• Consistency across platforms for structures or concepts added or modified
• Consistency between the changeset and the goal stated above
• Internal consistency with the rest of the library - is there any overlap between existing interfaces and any which have been added?
• Usage friction - is the proposed change in usage cumbersome or complicated?
• Performance and complexity - are there any cases of unexpected O(n^3) when iterating, recursing, flat mapping, etc?
• Concurrency concerns - if components are accessed asynchronously, what issues will arise
• Thoroughness of added tests and any missing edge cases
• Idiomatic use of the language

[kattrali]

I'd name this a bit more verbosely, like unsubscribeFromNotifications. There is an off chance that with a name like stop, it could be picked up erroneously in app review as a private API usage.