Fix for tty_size change
Implement B-test

The B-test is a test for the two-sample problem for high-dimensions.

This is an implementation of:
- Zaremba, W., Gretton, A., Blaschko, M. B-tests: Low Variance Kernel
  Two-Sample Tests (NIPS)
Merge pull request #17 from BigCrunsh/add_btest

Implement Block-test
Speed up implementation of B-test
Add B-test benchmark
Merge pull request #20 from JuliaStats/sjk/faster_btest

Speed up implementation of B-test
Fix Kruskal-Wallis

Test throw an InexactError() because rank sum might be non-integer for
ties.