created pdf
attemted cdf function - needs different beta function
added chisq pdf function; refactored some of the math helpers
added the cdf for chisq
added the cdf for chisq
added ppf for chisq
hyp2f1 function which works for some cases
still need a robust hypergeometric function
refactored 'mathhelpers' as 'math'
refactored special functions out of math utils