Similar to MomentEst_MixedBetaBinom, but allowing for slack on the SE parameter (see EMfit_betabinom_SEslack)

Similar to MomentEst_MixedBetaBinom, but allowing for slack on the SE parameter (see EMfit_betabinom_SEslack)

MomentEst_MixedBetaBinom_SESlack(
  ref_counts,
  var_counts,
  spr,
  spv,
  sprv,
  pi_RR_fix = NULL,
  pi_VV_fix = NULL,
  pi_het_fix = NULL
)