After discussing this with Mark, it seems clear that the old version of the
VariantEval FunctionalClass stratification is preferable to this version.
By reverting, we maintain backwards compatibility with legacy output files
from the old GenomicAnnotator, and can add SnpEff support later without
breaking that backwards compatibility.
This reverts commit b44acd1abd9ab6eec37111a19fa797f9e2ca3326.
3db457ed01