Incorrect normalization factor for 3D Rice distribution

[stestoll]

The normalization of the Rice function in

DeerLab/deerlab/dd_models.py

Line 119 in f7e0340

def _multirice3dfun(r,nu,sig):

is incorrect.

The first factor in

 P = nu**(n/2-1)/s2*r**(n/2)*np.exp(-(r**2+nu**2)/(2*s2)+nu*r/s2)*I_scaled

should be

 P = nu**(1-n/2)/s2*r**(n/2)*np.exp(-(r**2+nu**2)/(2*s2)+nu*r/s2)*I_scaled

Overall, this error has no effect, since P is numerically normalized afterwards.