updated thumb sync
ENYO-642: Updated documentation.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>
Merge pull request #961 from enyojs/ENYO-642-derekanderson

ENYO-642: TranslateScrollStrategy: Scroll thumb is not updated

Reviewed-By: Art Dahm (art.dahm@lge.com)
Integrated-By: Aaron Tam (aaron.tam@lge.com)