Making it about 10x faster, finding some previously missed cases and
fixing some previously wrong corrections.
This pulls in the `Collection.windows(ofCount:)` function from Swift
Algorithms.
* Add Example wrapper in order to display test failures inline when running in Xcode.
* Stop using Swift 5.1-only features so we can compile on Xcode 10.2.
* Wrap strings in Example.
* Add Changelog entry.
* Wrap all examples in Example struct.
* Better and more complete capturing of line numbers.
* Fix broken test.
* Better test traceability.
* Address or disable linting warnings.
* Add documentation comments.
* Disable linter for a few cases.
* Limit mutability and add copy-and-mutate utility functions.
* Limit scope of mutability.
Danny Mösch
JP Simard
Marcelo Fabri
Zev Eisenberg
Max Härtwig
Paul Taykalo