Add Person.find_or_update_from_hash(hash)
Hardcorest refactor of mal_import.rb

Seriously this shit is so fucking brutal omg
Or more accurately, I hate MAL with a passion
Move mal_import.rb to lib/
Fix mass assignment things to expose what we will need
Anime#get_metadata_from_mal --> Anime.create_or_update_from_hash
Add create_or_update_by_hash to Casting and Character
Person.find_or_update_from_hash --> Person.create_or_update_from_hash
Change mal_id to external_id in mal_import.rb
Add switch for @media in mal_import.rb
Handle featured characters within MAL instead of returning mal_ids[]
Handle empty synopsis case