Added exponential distribution
Added exponential distribution

ggonzale/jstat,ggonzale/jstat,akrawitz/jstat,jstat/jstat,NorthDecoder/jstat,smarden1/jstat,JeebsM/jstat,akrawitz/jstat,jamescgibson/jstat,JeebsM/jstat,cmpolis/jstat,jstat/jstat,smarden1/jstat,NorthDecoder/jstat