- Maybe deprecate makeFeatureDbFromUCSC(), supportedUCSCFeatureDb*(),
  and UCSCFeatureDbTableSchema() in BioC 3.22. Not a single Bioconductor
  package seems to be using this. Then defunct in BioC 3.23.

- makeTxDbFromUCSC(): Address the CDS non-completeness issue.
  The status of the CDS (complete or not) can be inferred from the
  cds*Stat field (when present) of the UCSC table.

