Ensure a component's nextTarget can be set

Of course, by default if there is non specified, use the
parentComponent. I'm purposefully going to prevent breaking the chain
if the nextTarget is falsy on components.

There is also now an example of redirecting the event target chain off
off of the componentTree
Differ event target path building strategies

Events originating from DOM targets remains DOM only in considering
target candidates.

Events originating from a Target uses the nextTarget facility in
considering target candidates.
Switch key-composer over to dispatchFocusdEvent

This is a half-baked transition; just enough to make sure it works in
theory. It's certainly not an exhaustive switch. I think the API may
warrant some changing with these results as usage of the keyComposers
is still confusing.
Visualize the application level event target chain

There ae better visualizations of course but this is a decent start.
Move eventListener API off of Object.prototype

More victories in consolidating dispatching responsibilities to
the Target; now the listener registration can be centralized here seeing
as these are the only objects that should be dispatching.

This does elevate Target to be a more vital concept, but it's sensible.

This may prove more disruptive than relocating the dispatching alone,
I haven't rigorously tested.