VectorDrawable native rendering - Step 3 of MANY

- Refactored VPathRenderer & VectorDrawableState
- Moved all the VD rendering into native
- Set up hooks for VD's property changes in JNI for animated VD

TODO: JNI calls can be further reduced when we convert the animation
in AVD to use RenderNodeAnimator, in which case animation will be
driven from native and therefore most of the JNI hooks for changing
VD's properties during animation will no longer be needed.

Change-Id: I52021f4d7bea057b83ace54085d870dd45acae0f