Description of feature

We should finalize naming for things. I'm starting a list here of things to resolve

• GeneRangesFilter -> GeneRangeFilter (since it only takes a single range)
• CanonicalFilter -> ???
• genes(cols=...) -> genes(columns=...) – Just to be more consistent. Could go the other way and use cols everywhere.
• What are the canonical strand names? +, - I assume?

Pushing to next release:

• GeneRangeFilter + TxRangeFilter + ExonFilter or all one RangeFilter as done in bioconductor?
• gf.ensembl.annotation Do we still want to call this an annotation? I named the function when the package was called genomic-annotations