docs(css): link and explain the default unminified css file
docs(css): link and explain the default unminified css file

fixes #819
fixes #788

algolia/react-instantsearch,algolia/instantsearch.js,algolia/instantsearch.js,algolia/react-instantsearch,algolia/react-instantsearch,algolia/react-instantsearch,algolia/instantsearch.js