BHV-10443 : Moonstone Component Bug for ExpandableListItem

Bug: Although header text area is tapped with 5-way button, the drawer does not open.
Fix: SpotlightFocus and tap event handling point are moved from header component to headerContainer component

DCO-1.1-Signed-Off-By: SoonGil Choi soongil.choi@lge.com
Add ExpandableListItemSample application(.js, .css, .html)
Add the up arrow displaying routin with/without spotlight when picker is open
Add 'Disabled ListItem' example in ExpandableListItemSample
Merge pull request #1380 from enyojs/BHV-10443-rc

BHV-10443 : Moonstone Component Bug for ExpandableListItem.

Looks good, thanks for the updates!

Reviewed-by: Aaron Tam (aaron.tam@lge.com)