span works wrong in point_source_p

[ldm78]

Using point_source_c the span parameter works like I would expect, i.e. if span=(0.1,0.1) the horizontal and vertical angles both go from -0.1 to +0.1.
With point_source_p the real range depends on the num_rays parameter, e.g.:

R=point_source_p(origin=(0,0,0),direction=(0,0,0),span=1.*pi/180.,num_rays=(4,4),wavelength=0.266,label="")
for r in R:
... print(np.arctan(r.dir[0])*180./pi)
...
0.0
0.0
0.24999762021038868
3.0616072830664826e-17
-0.24999762021038868
0.0
0.49998096249859053
6.123156277543506e-17
-0.49998096249859053
0.0
0.7499357530191801
9.184588695951347e-17
-0.7499357530191801

I believe the full angle span gets divided by num_rays instead of num_rays-1