Implement CoroutineAction

[jarkonik]

I've implemented Unity-like coroutines(but without Unity dependency) that can be used as actions

[meniku]

Hi @jarkonik that looks very useful, thanks. I'm gonna test it within the next days or so

[pan64271]

I have tried your implemetation in my game. When another node tried to stop the CoroutineAction node, it didn't stop immediately. It seems like you didn't take this case into consideration. So the DoStop method should be rewritten like this:

protected override void DoStop()
{
    Clock.RemoveTimer(Progress);
    Stopped(false);
}