Don't let NC pins escape the bounding box

[dnschneid]

If you have two parts with a huge number of NC pins on a schematic, you don't want the NC pins happening to line up with each other.

This edit folds the NC pins back into multiple rows to keep them within the bounds of the symbol. The number of NC pins needed to get them to collide internally is unrealistic even in contrived cases, at least as far as I can tell.