This adds one more skottie example and spruces up
the demos a bit (including making the star only
respond when you hold down the mouse)
No-Try: true
Docs-Preview: https://skia.org/?cl=156141
Bug: skia:
Change-Id: Ib577d6c06bd9784f4566d506150c451beadf1f1c
Reviewed-on: https://skia-review.googlesource.com/156141
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
1466af42a4