beta and f cdf inverses

[Brian Gough]

Jason Stover writes:
 > Attached is betadistinv.c, which will invert
 > the beta cumulative distribution function. Also
 > attached is a patch for fdist.c, gsl_cdf.h, Makefile.am
 > and test.c. Inverting the F distribution is (usually)
 > done by inverting the beta and transforming, so 
 > writing a gsl_cdf_beta_Pinv() gave me a gsl_cdf_fdist_Pinv() 
 > without much extra effort.

Thanks Jason. That looks good.

-- 
Brian Gough