Accessor for `colnames(colData(tds))`

[sgibb]

IMHO we need an shortcut/function to access the colnames of the colData slot.

For the Biobase::ExpressionSet or MSnbase::MSnSet this is fvarLabel (featureData slot).

Any suggestions for a good name?

Are our colData really featureData? If that's the case I would create an alias featureData for colData and would use fvarLabels for colnames(colData(tds)).

IMHO the features of an TopDownSet are the fragments so neither of the typical Biobase::phenoData nor Biobase::featureData fits.