DOC: mv otbRadiometricAttributesLabelMapFilterExample.cxx to RadiometricAttributesLabelMapFilterExample.cxx

ENH: In TSX calib, theta_loc is now estimated via least-square linear regression on the incidence angle records available

BUG: Odd registration key in itk : the tag is the position is the observer list, so it becomes invalid if another observer was removed before. Trying to overcome the problem by removing observers in the reverse order wrt the add order