usermanual: new extended section on geotagging thanks to Rudolf Martin
usermanual: fix for #10079
Don't use GnomeKeyring >= 3.12.0

They broke their API by deprecating the shit out of it and I don't feel
like cleaning up behind them. Merging libsecret support should be the
real fix.
Needed to fix some manufacturers madness
Scalepixels: new IOP

Needed to fix NIKON D1X non-square pixels madness
iop_dependencies.py: add scalepixels
Run iop_dependencies.py after merge!
Flip IOP: modify_roi_in(): drop sanity check

Causes garbage when used with scalepixels.
If it is really needed, it should be rewriten in a way, that has no side-effects like that.
OpenCL: move interpolation functions into separate header
OpenCL: move clip&rotate related stuff into separate file
OpenCL: move lens related stuff into separate file
OpenCL: move interpolation kernel into separate file
OpenCL: move lookup stuff into separate header
OpenCL: refactor clip_rotate_bilinear into interpolation_compute_pixel_bilinear_4f
OpenCL: refactor clip_rotate_bicubic into interpolation_compute_pixel_bicubic_4f
OpenCL: refactor clip_rotate_lanczos2 into interpolation_compute_pixel_lanczos2_4f
OpenCL: refactor clip_rotate_lanczos3 into interpolation_compute_pixel_lanczos3_4f
OpenCL: refactor clip_rotate src pixel coord calculation into function
Scalepixels IOP: OpenCL