Fixes ENYO-410

## Issue
Current spotlight container events rely on bubbling spotlight focused/blur events up from spotted controls. This causes (at least) 2 issues:
* If the originating blur/focused event is stopped by a handler returning true, the container events are never fired
* When moving between containers, the enter/leave events fire in an unnatural order. Specifically, the enter event fires before the leave event.

## Fix
Move trigger for spotlight container events to `_setCurrent()` in enyo.Spotlight and explicitly fire instead of waiting for the regular spotlight events to bubble up the the container

Enyo-DCO-1.1-Signed-off-by: Ryan Duffy (ryan.duffy@lge.com)