Readme file update

I updated a bit the readme file.

I have also some suggestions regarding the rest client:
1) The client is doing only GET requests for the moment, or the API provides other calls that uses the POST, PUT and DELETE verbs. So I guess you need to support them also later.

2) During the user login (python get_oauth_headers.py) you are asking the user to visit a URL like: "Please VISIT this page to grant resource authorization:", but you could simply open directly the browser to this URL.