baq: Implement final BAQ score transformations
baq: Implement final BAQ score transformations

Mimics the same transformations applied by GATK.

[git-p4: depot-paths = "//sw/gpgpu/nvbio/bqsr/": change = 18902501]

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