Showing a problem with SceneCache SOP loading a PointsPrimitive.

The points are doubling up on each cook, because they aren't linked to any Houdini primitive.
Removing code that wasn't doing anything
Adding a ParticleSystem in ToHoudiniPointsConverter
PointsPrimitive Uniform prim vars are now converted.

Since we have a ParticleSystem for each PointsPrimitive, we can support conversion of the Uniform prim vars to Houdini PrimAttribs.