Significance test flags #20
Description
Right now, we always perform a t-test exactly when we have two input samples. We should add flags to disable/enable this, and perhaps perform tests on all input files when there are more than two. For example, given input files a, b, and c, we could either run and display t-tests for {a, b} and {b, c} (compare the sequential pairs), or compare every two-element subset of {a, b, c}. The former is probably more useful in practice.