Add national dex numbers for Kalos Pokémon.
Split Pokédex version groups into their own table again.

spline-pokedex doesn't need to adapt; Pokedex.version_groups looks the
same as always and VersionGroup.pokedex wasn't used anywhere.
Set colour, shape, and growth rate for Kalos Pokémon.

That's everything trivial that goes on pokemon_species.