Preware: Initial Package List UI Implementation

* Add 'icon' property to ListItem
  (Displays icon if true)
* Give the show functions more obvious names
* Use an enyo.Repeater & ListItem for Package List
* Populate list from preware.PackagesModel.packages
* Remove isScreenNarrow check from main panel index change

Signed-off-by: Josh Palmer <jpalmerwatkins@me.com>