Take detector orientation in account when converting from PONI to ImageD11

[loichuder]

Fix #2090

Followed the mapping of

pyFAI/src/pyFAI/geometry/imaged11.py

Line 174 in 74c73f9

if (o11, o12, o21, o22) == (1, 0, 0, -1):

[kif]

Hi Loic, thanks for addressing this "todo".
The code in itself looks great but the tricky thing is in the signs of the coefficients...

http://sylvana.net/jpegcrop/exif_orientation.html

• Orientation3 is the default in pyFAI, the historical one. The fast scanning axis is flipped because we are looking from the sample and not from behind the camera.
• Orientation 1&2 on the one hand and 3&4 on the other should only see a flip along the fast direction, which looks OK
• Orientation 2 & 3 on the one hand and 1&4 should only differ in the vertical direction (or slow direction), so there should be only one sign change. This is likely wrong.

I will let James comment further on this @jadball.