v0.20.0-alpha1

• Changes below are considered breaking.
• Change all occurrences of EventsLoop to EventLoop.
• Previously flat API is now exposed through event, event_loop, monitor, and window modules.
• os module changes:
  • Renamed to platform.
  • All traits now have platform-specific suffixes.
  • Exposes new desktop module on Windows, Mac, and Linux.
• Changes to event loop types:
  • EventLoopProxy::wakeup has been removed in favor of send_event.
  • Major: New run method drives winit event loop.
    • Returns ! to ensure API behaves identically across all supported platforms.
      • This allows emscripten implementation to work without lying about the API.
    • ControlFlow's variants have been replaced with Wait, WaitUntil(Instant), Poll, and Exit.
      • Is read after EventsCleared is processed.
      • Wait waits until new events are available.
      • WaitUntil waits until either new events are available or the provided time has been reached.
      • Poll instantly resumes the event loop.
      • Exit aborts the event loop.
    • Takes a closure that implements 'static + FnMut(Event<T>, &EventLoop<T>, &mut ControlFlow).
      • &EventLoop<T> is provided to allow new Windows to be created.
  • Major: platform::desktop module exposes EventLoopExtDesktop trait with run_return method.
    • Behaves identically to run, but returns control flow to the calling context and can take non-'static closures.
  • EventLoop's poll_events and run_forever methods have been removed in favor of run and run_return.
• Changes to events:
  • Remove Event::Awakened in favor of Event::UserEvent(T).
    • Can be sent with EventLoopProxy::send_event.
  • Rename WindowEvent::Refresh to WindowEvent::RedrawRequested.
    • RedrawRequested can be sent by the user with the Window::request_redraw method.
  • EventLoop, EventLoopProxy, and Event are now generic over T, for use in UserEvent.
  • Major: Add NewEvents(StartCause), EventsCleared, and LoopDestroyed variants to Event.
    • NewEvents is emitted when new events are ready to be processed by event loop.
      • StartCause describes why new events are available, with ResumeTimeReached, Poll, WaitCancelled, and Init (sent once at start of loop).
    • EventsCleared is emitted when all available events have been processed.
      • Can be used to perform logic that depends on all events being processed (e.g. an iteration of a game loop).
    • LoopDestroyed is emitted when the run or run_return method is about to exit.
• Rename MonitorId to MonitorHandle.
• Removed serde implementations from ControlFlow.
• Rename several functions to improve both internal consistency and compliance with Rust API guidelines.
• Remove WindowBuilder::multitouch field, since it was only implemented on a few platforms. Multitouch is always enabled now.
• Breaking: On macOS, change ns identifiers to use snake_case for consistency with iOS's ui identifiers.
• Add MonitorHandle::video_modes method for retrieving supported video modes for the given monitor.
• On Wayland, the window now exists even if nothing has been drawn.
• On Windows, fix initial dimensions of a fullscreen window.
• On Windows, Fix transparent borderless windows rendering wrong.