darktable/ART searches for the optimal value of a parameter starting
with the currently set value. They scan within a range of that value.
This commit changes the starting value to 0 for rotation, pitch, and
yaw. It makes the search range balanced.
Comment out parameters that darktable/ART use in case we decide to use
them later. Add yaw and pitch parameters used by the camera-based
perspective correction. Modify homography matrix calculation to use the
camera-based perspective model.