Do not optimize draw image if target driver does not support npot

If the target driver does not support npot image, we must create a
pot image, paint the original image to pot image.  In this case,
optimization of image draw does not have much sense because
we have to first draw the pot image. In this case, we disable image
drawing optimization.  Fortunately, most of modern driver (including
es3 drivers) support npot image tiling
Detect the direction of oval while using addOval method in SkPath.

While drawing oval using arcTo method of SkPath, detect the
correct direction of oval whether it is CW or CCW and invoke addOval
method with appropriate direction.