Performance increase idea

[derrickpelletier]

when the current row intersection is performed, and the poly is returned which represents the parts of the original poly that fall within the current row, rather than starting at the leftmost edge of the current row in the entire bounding box, we really only need to start at the leftmost edge of the bounding box of that poly that was returned.
and similarly end at the eastern extent.

This would save a lot of wasted checks. A turf.extent() would need to be performed for every row.