Enhancements for UIThread.Bind()

[Kouji Matsui]

• Add Awaitable<bool> UIThread.TryBind(): Because some minor timing will be caused exceptions on UI shutdown process.
  It's returns false when binding is faulted.
• Add UIThread Bind(Action action): Same as WPF's Dispatcher.BeginInvoke(...)
• And varies of these patterns overloads.

[Kouji Matsui]

Refer: kekyo/FlashCap#8

[Kouji Matsui]

Deploying 1.5.2

[Kouji Matsui]

Verified by FlashCap.