Houville :: put points in the centre of prims

Points in centre of prim, and delete points:

addpoint(0, @P);
removeprim(0, @primnum, 1);

==EDIT== Just realised it can be handy to pull attributes from the prim on to the newly created points in the same primwrangle.
Here's how:

int newPt = addpoint(0, @P);
addpointattrib(0,"N",{0,0,0});
setpointattrib(0,"N", newPt, @N, "add");
removeprim(0, @primnum, 1);