Forward declaration of camera vector for PinholeCamera<Cal3Fisheye> and PinholeCamera<Cal3Unified>.

Extend python wrapper to include fisheye camera models Cal3Fisheye and Cal3Unified.

Extend python wrapper to include fisheye models.

Forward declaration for Set of Fisheye Cameras

Forward declaration of PinholeCal3Fisheye needed by Python wrapper.

Test projection function and factors using a stereoscopic (xi=1) reference model, i.e the image height is given by y = 2 f tan(theta/2).

Test case fails if object depth z is not equal 1.

For the equidistant fisheye model, r/f = tan(theta), the Gauss-Newton search to model radial distortion is expected to converge faster by mapping the angular coordinate space into the respective tangent space of the perspective plane. This is consistent to the nPlaneToSpace initial projection used in the calibrate() function of the omnidirectional model (Cal3Unified).

Without declaring calibrate / uncalibrated in the interface specification, the functions of the Base class Cal3DS2_Base is called.
The layout of the optional Jacobian matrix is 2x10 in Cal3Unified and 2x9 in Cal3DS2_Base, so this are different function calls.

Add pybind specialisations for CameraSetCal3Unified and CameraSetCal3Fisheye.

Currently triangulatePoint3 returns wrong results for fisheye models. The template for PinholePose may be implemented for a fixed size of variable dimensions.