Added stopAtEnd property to SpriteAnimations.

Enyo-DCO-1.1-Signed-off-by: Blake Stephens <blake.stephens@lge.com>
Merge pull request #855 from enyojs/BHV-13456-blakestephens

BHV-13456: Added stopAtEnd property to SpriteAnimations.

Reviewed-By: Cole Davis (cole.davis@lge.com)