0.21.1

• Improved performance of coroutine dispatching (DispatchTask instance is no longer allocated).
• Fixed Job.cancel and CompletableDeferred.complete to support cancelling/completing states and properly wait for their children to complete on join/await (see #199).
• Fixed a bug in binary heap implementation (used internally by delay) which could have resulted in wrong delay time in rare circumstances.
• Coroutines library for Kotlin/JS:
  • Promise.asDeferred immediately installs handlers to avoid "Unhandled promise rejection" warning.
  • Use window.postMessage instead of setTimeout for coroutines inside the browser to avoid timeout throttling (see #194).
  • Use custom queue in Window.awaitAnimationFrame to align all animations and reduce overhead.
  • Introduced Window.asCoroutineDispatcher() extension function.