Update admin panel to use new MALImport system
Squash some bugs in various create_or_update_from_hash methods

Anime:
 * fix title handling to use new title field format
 * remove TODO comment
 * show_type corresponds to hash[:type] not hash[:show_type]
 * compact to remove nils
 * handle characters without voice actors better (I hope)
 * return created/updated/found anime item

Casting:
 * handle character casting without a VA

Person:
 * compact to remove nils
Move convert_age_rating out to mal_import.rb