Positions the iterator at the cell containing "target". If no such cell
exists, returns false and leaves the iterator positioned arbitrarily.
The returned index cell is guaranteed to contain all edges that might
intersect the line segment between "target" and the cell center.
Positions the iterator at the cell containing "target". If no such cell exists, returns false and leaves the iterator positioned arbitrarily. The returned index cell is guaranteed to contain all edges that might intersect the line segment between "target" and the cell center.