README.md updated

Hi, I suggest updated version of README. Could you check whether it changes original meaning or not ?

There're a few things I don't understand their meaning clearly are:
> DataHandler trait which isn't depended specific data storage 

Does this means DataHandler trait itself does not depends on specific data storage ? If so, what's the point here ? I don't understand why you mention this here and thus omit this sentence on my updated version.

> If you want to handle the oauth flow more customizable, it would resolve using Token/ProtectedResource#handleRequest directly.

This means user needs to modify some provided traits (Token / ProtectedResource ) directly when he/she want to change the OAuth workflow itself, doesn't it ?

Thanks!