OpenCL Jitter SOP

Jitters vector point attributes in random directions.

This operator has a lot of advantages over the Point Jitter SOP:

1. OpenCL acceleration.

2. VEX code branch.

3. Ability to specify which attribute to jitter.

4. Ability to specify the jitter direction as an attribute.

5. Ability to use a weight attribute.

6. Preserves the point normals of isolated points after they are recomputed.