I have turned histogram into a struct; it still needs a dummy int beside it because only plain ints can work as Q_PROPERTIES
The histogram doesn't resize, and there are some hardcoded numbers that ought to be linked so that they don't go out of sync, but this is basically what I wanted.
Made the post-filmulation histogram semilog
Added image rotation (compulsory, not settable yet), tweaked the post-filmulator histogram, and made loading a new image use all of the slider settings without ignoring them.
I tried dealing a little with color; I added some ways to get at the color in LibRaw. I also fixed the histogram resizing business.