Change report instance margins from transparent to white
At some point some months ago, I noticed report pdfs having transparent, instead of white, backgrounds, which make them hard to read. With certain viewers you can't tell, but with Photoshop and os x's Preview you can. I see they're transparent in trunk and 2.1.0. I'm not sure if they've always been this way and it's just that Preview was updated, or if it's due to a change in reporting.