1. Changed m1_Vbeta_inv_Sigmabeta_j_draw_rdd_key_h2 to not include groupByKey, correspondingly changed iteration levels in get_substructure_beta_mu_j ot one level up for obj[1][0]
2. Changed function get_Vbeta_i to include Vbeta_inv_j_draw from m1_Vbeta_inv_Sigmabeta_j_draw_rdd_key_h2 object