Numerous small bug fixes, dead code removal, formatting consistency, removed implementation deails from interfaces, etc

[BMurri]

Bug fixes:

• Used enumeration extension to ensure that paged list APIs will, if needed, pull all items (instead of just the first page) (see ToAsyncEnumerable.
• Added scope to singleton app cache keys.
• Ensured that async methods inside non-async methods were calling the async methods in such a way to ensure that the data requested would really be returned (see AsTask).
• Fixed bugs parsing exceptions and in a finally block where the cleanup code would never have worked as written.
• Fixed some grammar and wording in messages.

Removed unused code, except for code referenced in commented out code. There, I commented it out.

Moved some code out if places it probably should never have been placed originally (yes, I'm the one that placed it there ;)).

Made some code edits to make formatting more consistent (sometimes within a given file, sometimes across the codebase).