WeakEventListener usage holds strong reference

[jianchun]

Suspect the usage of WeakEventListener is incorrect. E.g.,

var weakEvent = new WeakEventListener<AdaptiveTrigger, CoreWindow,
                                     WindowSizeChangedEventArgs>(this)
{
    OnEventAction = (instance, s, e) => OnCoreWindowOnSizeChanged(s, e),
    ...
};

private void OnCoreWindowOnSizeChanged(CoreWindow sender, WindowSizeChangedEventArgs args)
{

OnEventAction is assigned an lambda. The lambda captures this (implicitly as this.OnCoreWindowOnSizeChanged). Thus weakEvent holds a strong reference to event target this.

Thanks for this inspiring project!