Optimal params for optical flow tracking. Some small box fixes.

AlexeyAB

2018-02-08 be90b8e8cb6bbf3951a5e185aa43ccfdd4a03f4d

1
2
3
+++++
val_eq (Val.add (Val.add (r3 PC) Vone) Vone) (Val.add (x2 PC) Vone)
*****