fix for BHV-16168 select method delay

Issue.

The root problem is that all of the methods for the `DataList` are deferred, but the `_select` method was inherited from the `DataRepeater`, and is not deferred. This causes the `_select` method from the repeater to ask for controls from the vertical delegate, which is out of sync.

Solution.

Extend the _select method for the `DataList`, and standardize the way it is called, by utilizing the deferred construct of other methods. Without needing to edit the absoluteShowingChanged method, I used `enyo.asyncMethod` to ensure that inherited `_select` method would be executed at the end of the stack.

Enyo-DCO-1.1-Signed-off-by: Derek Anderson <derek.anderson@lge.com>