Scalable Grid

I've started on doing the scalable grid stuff today. A lot of the code will need to be scraped and redone in order for this to work properly, but at the very least I've managed to get some of the basic stuff working already. At this point, the new shipping grid scrolls in the correct direction now, at a 1:1 speed to the mouse in both axes, which is a really nice improvement. There's still a lot more that will need to be done before it'll be usable, though, so I'll keep you all updated on that.

Here's a short recording I did which shows the basic functionality of the new TableElement class.