Scperturb

- Allows a list for control
- Parallelized all e-distance functions for speedup

Fixes issue 10: edist now uses sample corrected edistance formula per default.

Parallelized the E-test using joblib.Parallel. For now using n_jobs=-1 (thanks Lukas Heumos).

- pvalue minimum now 1/runs in e-test instead of 0
- Massive increase in computation speed of both etest and edist
- R version on github see package_r

Initial pre-release of scperturb as a python package.