- Changes internal target_os flags to be feature flags; macOS is now
appkit, and iOS/tvOS are now uikit. This enables platforms that are
not Apple-specific platforms that use frameworks to be compiled for.
- Updates the examples to handle closing/quitting better.
- Adds support for NSSplitViewController.
- Reworks NSMenu support to be cleaner with enum variants.
- Reworks the Foundation underpinnings to be a bit safer and more clear
in how they're used and passed around.
- Changes to docs structure for push towards v0.1.
- Examples updated to account for changes.
