[up] Batch one-sample test with >1 covariates

The batch version of one-sample tests can now deal with more than 1
covariates (tested).
[new] One-sample and two-samples tests

Testing code for one-sample and two-samples tests.
[up] Batch two-sample with >1 covariate

Implementation and testing of batch with more than one covariate in a
two-sample test.