Add support dynamic system env config lookup. Example:
config :amazon_books,
associate_tag: {:system, "AMAZON_ASSOCIATE_TAG"},
access_key_id: {:system, "AMAZON_ACCESS_KEY_ID"},
secret_access_key: {:system, "AMAZON_SECRET_ACCESS_KEY"}
- Default to US service URL if invalid country given
- Include ASIN and lowest offer in result
- Move offer out of nested map
- Fix Elixir 1.4 warnings
- Include ISBN, EAN, publisher, # of pages, price and currency in the response map.
- All lookup and search functions return a list. The previous version returned XML string in case of ISBN lookups.