Fixed a bug multiplying x0(ii,7) in the wave field loop
Changed sign of WFS driving function weight for focused sources
Changed sign of WFS pre-filter
Changed the way the WFS pre-filter is applied to a given ir
Updated wave_front_direction() to 3D
Remved no longer needed wave_front_time

This functionallity is also in the other wave front function, which I renamed to
wave_fronts_wfs()
Updated default conf.N value and renamed brs settings to SSR
Moved weights_for_points_on_a_sphere_rectangle() and fixed comment
replaced nargchk with narginchk
Updated license statements