WIP: Describe array order terminology in 2D, 2D+c, 3D, 3D+c arrays

Still working on it, but just thought I'd check this in so that we can tag it as 0.11.
ASCII art is always an option!

I think dipy ships a small head MRI with their package. (128x128x something) It's likely already BSD licensed - I don't think it's all that large, either.