Handle NYPL Stereogranimator rotation in `nypl_recrop.rb`

[ryanfb]

Some NYPL Stereogranimator images have some amount of rotation applied, exposed in the rotation field in the JSON, e.g. http://stereo.nypl.org/view/89612.json has "rotation":"0.19999999999999998". We should figure out how to take this rotation into account when cropping high-res originals. Presumably we can rotate the thumbnail and original by this amount before applying the rest of the process, but it's a little unclear how the rotation is applied and how it affects the image: What does the value mean (clockwise, counterclockwise, units)? Do we rotate about the center, or a corner? Do the x1,y1,x2,y2 variables still index into a rotated image that has the same dimensions as the original thumbnail image?

[mgiraldo]

eg: this photo

when you rotate in the stereogranimator, the image is always “inside the box”. notice the top-left corner of the image moving right:

the resulting rotation, "2.500000000000001" (i should convert that to float in the json 😳) is clockwise (positive).

the x1, y1, x2, y2 crop values are still relative to the containing “box” therefore the master TIFF must be:

1. cropped according to the low res version (solved already, which hopefully accounts for any non-stereogranimator rotations)
2. cropped version rotated in the same way as in stereogranimator
3. each frame cropped as in stereogranimator