Make output format more consistent

[wvengen]

When it is unknown whether the fish was caught or raised using aquaculture, the output format is unsuitable. This was encountered with the flat parser, which may return methods and areas (instead of catch_areas, catch_methods, aquaculture_areas and aquaculture_methods).

It would be clearer to use the following output format:

[
  {
    :names =>   [{ :common=>"Alaska pollakfilet", :latin=>nil }],
    :areas =>   [{ :text=>"de Stille Oceaan", :fao_codes=>[]}],
    :methods => [],
    :kind =>    "caught",
  },
]

This would have the following benefits:

• consistent output format (also when kind is unknown)
• allow returning kind when no area or method is found (see also Parse area when method unknown #3)

Note that this breaks the API, requiring a major version bump.