0.22.3

• Fixed produce builder to close the channel on completion instead of cancelling it, which lead to lost elements with buffered channels (see #256).
• Don't use ForkJoinPool if there is a SecurityManager present to work around JNLP problems (see #216, PR by @NikolayMetchev).
• JS: Check for undefined window.addEventListener when choosing default coroutine dispatcher (see #230, PR by @ScottPierce).
• Update 3rd party dependencies:
  • kotlinx-coroutines-rx1 to RxJava version 1.3.6.
  • kotlinx-coroutines-rx2 to RxJava version 2.1.9.
  • kotlinx-coroutines-guava to Guava version 24.0-jre.