Add Kruskal-Wallis ranking and Kruskal-Wallis Test
`kruskalWallis` now ranks samples
Add `kruskalWallisTest`
Add more Kruskal-Wallis tests
Add documentation for Kruskal-Wallis module
Correct documentation about bug seriouseness
Calculate quantiles for normal distribution in numerically
stable way

old method losed precision for small p. Expression (1-p) was at fault
correct way is to flip sign of erfc after computation

Fixes #64
Fix integer overflow problem
Fix subtle bug in calculation of jackknifed unbiased variance
Bump version to 0.11.0.2
Added tag 0.11.0.2 for changeset f1452afc54f0
Merge
Bump version to 0.11.0.3
Added tag 0.11.0.3 for changeset c75dd236003c
Small changes

 - Inline square function
 - Improve readability
Improve readability a somewhat

N.B. current implementation of mean uses Welford algorithm which
is less numerically robust than KBN summation it's more readable
Add module header
Merge branch 'kruskal-wallis'
Remove some unfortunate uses of INLINE
Drop a ton more uses of INLINE

--HG--
extra : amend_source : c838454f332970db35c7bad687558e146ae6043e