Alternate definition of mean, variance for Categorical distribution.
logpdf implemented for Dirichlet distribution
Switch basic univariate types to immutable's

Replace expr() with Expr()
Replace randi() with rand(1:n)
Merge pull request #28 from JuliaStats/immutable

Switch basic univariate types to immutable's
Finish transition to immutables
Algorithm AS 176
Fix scaling bug
adding inverse gamma distribution
adding inverse gamma distribution
Merge branch 'inversegamma' of https://github.com/danmerl/Distributions.jl into inversegamma

Conflicts:
	src/Distributions.jl
fixing dumb bugs, adding cdf for inverted gamma rvs
adding modes function and adding more efficient rand! for invertedgamma
Adding quantile function and reparametrizing so things are consistent between the gamma and inverse gamma implementations.
Merge pull request #30 from danmerl/inversegamma

Adding InvertedGamma random variables
Merge pull request #25 from sbos/master

logpdf implemented for Dirichlet distribution
initial stubs for wishart and inverse wishart samplers
Working Wishart and Inverse Wishart random matrix generators
Merge branch 'wisharts' of https://github.com/danmerl/Distributions.jl into wisharts

Conflicts:
	src/Distributions.jl
adding pdf methods for wishart and inverse wisharts
Full tested the pdfs against R, better error checking