ensure we don't reuse (and subsequently modify) an original array passed into the constructor

Enyo-DCO-1.1-Signed-off-by: Cole Davis <cole.davis@lge.com>
add unit test to ensure adding/removing/adding records will properly affect DataList

Enyo-DCO-1.1-Signed-off-by: Cole Davis <cole.davis@lge.com>
Merge pull request #471 from enyojs/repeater-collection-fix

DataList and Collection fix/unit-test

Reviewed-By: Ben Combee (ben.combee@lge.com)