Added BSD-license and completed the likelihood ratio test

The likelihood ratio test is working now.
Also, the whole project is now licensed under BSD-3.

Bug fix release

Improved documentation and installed versioneer

Release for t-test, wilcoxon and wald test and enrichment.

LRT is not functional yet. the documentation and api of the package were changed and extended. Wald test should work better than in v0.1.0. The api is not backwards compatible but is planned to be backwards compatible from now.

Initial release for alpha usage

Wald, t-test and wilcoxon are functional. The skeleton of the API is in place and major changes to the current API are not planned, however, new features will be added.