diffreport: More stringent error criteria
diffreport: More stringent error criteria

Remove the waiver for off-by-one errors on discretized values. Flag
errors when Firepony is more than 0.001% off from GATK.

broadinstitute/firepony,NVlabs/firepony,broadinstitute/firepony,NVlabs/firepony,NVlabs/firepony,NVlabs/firepony,broadinstitute/firepony,broadinstitute/firepony