Bhattacharyya Coefficient of two distributions
bhatt_coeff_brt.RdCalculates the Bhattacharyya Coefficient (BC) between two distributions. BC is the sum of the square root of the multiplication of the elements in bin i for both distributions. It ranges from 0 (no overlap) to 1 (full overlap). v.0.1. Used within eval_brt. Included to ensure functionality.