configurable origin/size on octree creation

[marado]

I suggest to change the ABI by changing the creation input, getting a mandatory ([ox,oy,oz],radius).

We can have default values for null.

My doubts is on wether we should use a radius (forcing the octree to represent a cube) or not. And, if not, if we should get only a set of x,y,z sizes (forcing the origin to be the center of the cube), or a set of ranges (lower-x, higher-x, lower-y, higher-y, lower-z, higher-z).

If we change the ABI, we should do a version bump with this change.