added Bhattacharyya coefficient, distance and hellinger distance metrics and tests, not yet tested in pairwise mode though
added another set of tests for hellinger et al
a few more tests for hellinger et al
added colwise benchmarking of Hellinger et al distances
added comment to make it clear that the Bhattacharyya et al distances assume vectors to be compared are probability distributions, frequencies or counts
updated README, don't export the coefficient
added test to ensure it is semimetric, clearer comment
simplified so Bhattacharyya coefficient is no longer a metric, just a sub-function we call
Merge pull request #23 from robertfeldt/master

Added Bhattacharyya and Hellinger distances