Implement:

* F-distribution

* Beta distribution

* Kolmogorov-Smirnov distribution

* Maxwell distribution
  http://mathworld.wolfram.com/MaxwellDistribution.html

* Levy distribution
  http://en.wikipedia.org/wiki/L%C3%A9vy_distribution

* Zipf distribution
  http://en.wikipedia.org/wiki/Zipf%27s_law

* Hypergeometric distribution

* Rayleight distribution

* and other distributions
