Explain rate limiting

[doup]

From the documentation is not clear how this library handles rate-limiting.

What happens if I try to fetch too much data, too fast. Will it internally pause until it's safe to continue? So, for me -as a library user- will be transparent and I'll get my data eventually?

Thanks!

[alkihis]

Since #47 is merged, you now have some explaination of rate limit handling inside this lib :)