Fix bad styles being cached in massive lists

[nickclaw]

In lists large enough to trigger scaling, the cached styles can be invalid. Causing weird banding effects and overlapping as you scroll.

[bvaughn]

Nice fix.

Supporting this feature (max scroll offset) is a huge pain in the ass. I wish I didn't have to support it. :/

[bvaughn]

This seems like an arbitrary/odd rowCount value. What's the logic?

[nickclaw]

Well, the height of the inner container needs to be over DEFAULT_MAX_SCROLL_SIZE to trigger this. Doing DEFAULT_MAX_SCROLL_SIZE / rowHeight will get us exactly enough rows to fill the container -- so I figured I might as well double it to be sure :P

I'm happy to add comments explaining it, or if you have a better suggestion for the test use that.

[bvaughn]

Ah, I see. I think the order of operations threw me a bit. (It's late here.) It's fine as is. :)

[nickclaw]

I can tell haha, writing the ScalingCellSizeAndPositionManager alone looked like enough to make one go crazy

[bvaughn]

I have hopes that the new layout algorithm in PR #515 might totally change the way scaling is done- making things like offset-adjustments and ScalingCellSizeAndPositionManager unnecessary. But it's still kind of an experiment. It might not pan out.