[BREAKING CHANGE] Major work on Windows Runtime APIs, with huge thanks to
Halil Durmus (@halildurmus). Breaking changes are limited to WinRT APIs, which
are now more idiomatic for Dart. Includes full implementation of
Windows.Globalization.Calendar that is the new reference design for WinRT
APIs.
Restructure generation code into a separate package.
Use super parameters introduced in Dart 2.17, with matching dependency
upgrade.
Tidy up examples to include consistent headers.
All files now have lower case names (e.g. IUnknown.dart -> iunknown.dart)