add motion blur params to skottie2movie

--motion_angle ... [default is 180]
--motion_samples ... [default is 1, for no motion blur]

Change-Id: Iec0f31655b3369f51e0b398efb2d5b156dcbaf2e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/221416
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
5 files changed