Requirements allow argparse to be loaded from an external repository.
Update Species to allow longer names.
Completely overhauled the way reference data is managed.

* Merged the reference data files for Activity, Age, Direction, Plumage,
  Protocol and Sex into a single file. The number of records will always be
  small so managing all the translations will not be difficult.

* (Species) Rank is now also handled by a single file however the data was
  replaced with the names used by eBird.

* Completely overhauled the way the reference data for Species and
  SpeciesGroups which makes it way easier to manage. A single file,
  taxonomy.csv, which is published by eBird is used to load all the Species
  and SpeciesGroup records. From this a subset of records can be selected
  and translations for common names loaded using species checklists published
  by Avibase. Then all the records for species that occur outside a given
  geographical area can be removed making the process of managing the species
  table much easier.
Updated version number for release
Merge branch 'release-0.4.8' into develop