Add test data vectors
Fix typeclass restrictions on gammaFunc and add gammaPDF
Add PDF, parameterised with alpha and beta
Add typeclass constraints on pocahammer function
Added Num a typeclass constraint to factorial
Change typeclass constraint from Integral to Floating
Fix function typeclass constraints
Add module, Lower Incomplete Gamma function
Add linear congruity generator

This commit adds the LC Generator to the StatUtils.hs file. This
consisted of implementing a single function to generate the next
value given a seed, followed by a function to generate a list,
and finally, the user function to generate what I hope is a sample
of pseudorandom numbers distributed as Unif(0,1].