grad_offspring_original: Gradient of 'obj_offspring' using the original...
In dcgerard/updogAlpha: Using Parental Data for Offspring Genotyping

Gradient of obj_offspring using the original parameterization.

1	grad_offspring_original(ocounts, osize, ploidy, prob_geno, d, eps, tau)

`ocounts`	The observed counts of the refernce allele for each individual.
`osize`	The observed number of reads for each individuals.
`ploidy`	An integer. The ploidy of the species. This is assumed to be the same for each individual.
`prob_geno`	The allele frequencies of the genotypes. See `get_prob_geno`.
`d`	The sequencing bias parameter.
`eps`	The sequencing error rate
`tau`	The overdisperion parameter.