Split data

Having packs is great but a lot could be mutualized (and make the files smaller).

The change is basically as follow:

• Move families and genera in separate files
• Reference these files in the packs This way, for a given locale, packs only contain the resources.

Example:

# data/fr/families.yml
---
:data:
- :name: Something
  #...

# data/fr/genera.yml
---
:data:
- :name: Something
  #...

# data/some_pack.yml
---
:families: fr/families.yml
:genera: fr/genera.yml
:resources:
- #...

This is a big breaking change, as clients will need to implement multiple file support.