Transform in an spe file with coords in the 4D space defined by crystal Cartesian coordinates
and energy transfer.
Allows for correction scattering plane (omega, dpsi, gl, gs) - see Tobyfit for conventions
It is an interface function to private cal_proj_matrix function,
the interface is used to compare the results, obtained from this function
with e.g. Mantid results;
% Overloaded methods:
sqw/get_test_calc_projections
sqw/get_test_calc_projections