GeneralizedBetaDistribution.ProbabilityDensityFunction does not have an area of 1

[arubiomoreno]

The PDF should have an area of 1 by definition. The current implementation has an area of Support.Length. The fix is as simple as changing this line:
return constant * Math.Pow(z, alpha - 1) * Math.Pow(1 - z, beta - 1);
for this line:
return constant * Math.Pow(z, alpha - 1) * Math.Pow(1 - z, beta - 1) / Support.Length;

Edit: check also GeneralizedBetaDistribution.LogProbabilityDensityFunction

[cesarsouza]

Hi Arubio,

Huge thanks! I will commit the fix in a moment, after all the unit tests finish passing.