More Snap options ( Corners / Edges / half-grid )

Snap to grid is great but it would be nice to snap to edges or corners. Currently I'm trying to add pillars and would like it in a corner of 4 squares not the center of one. This will also be nice for objects that you want to make larger such as turning a 1 square to 4 square object.

So I'd love a toggle to be able to set an object to snap to; edge, corner, center, or none.