desc: Volume adjusted version of stereo_widening

slider1:1<0,10,0.01>width

in_pin:L in
in_pin:R in
out_pin:L out
out_pin:R out

@slider
tmp = 1/max(1 + slider1,2);
coef_M = 1 * tmp;
coef_S = slider1 * tmp;

@sample
s0=spl0;
s1=spl1;

m = (s0 + s1)*coef_M;
s = (s1 - s0 )*coef_S;

spl0 = m - s;
spl1 = m + s;
