Domenico Tiziani / gammalib

The GModelSpatial::region() method returns a pointer to a sky region that fully encloses the spatial model component.

…ients argument (#1847)

The eval_gradients() methods duplicate much of the code of the eval() methods. To increase the maintainability of the code, the eval_gradients() methods have been removed, and the computation of partial derivatives is now done by the eval() methods if the optional gradients argument is set to true.