FeatureTagMatch takes an `*aha.Feature` and cmopares it to a tagFilterMap, returning `true` if there's a match and `false` if there isn't.

GetReleasesAndFeaturesForProductsAndQuarters returns releases and features given a product and date rate.

NewFeatureSetForReleasesIds returns a new FeatureSet given a list of ReleaseIds.

Feature is struct with additional properties to search on, notably ReferencePrefix.