Merge pull request #7 from agbeltran/dev

Built reduced OBI import.
Merge pull request #8 from agbeltran/dev

onto-release code
adding quantile, percentile, decile, replacing data item by quantile in q-q plot axioms, adding alternative terms to man-u test and kruskall-wallis test
Update README.md
adding design matrix class, metadata and restriction, to be reviewed before closing issue, reasoning ok
adding one-sided and two-sided tests, related hypothesis, contrast placeholder, adding restriction regarding skewness to normal, exponential student distribution, editor notes to 1% false positive rate
fixing relation on skewness for a couple of distribution
Changed condition for 'one tailed test', assigned URIs