Update readme.markdown
Refactored the setup of user/pass in the tests

Best to only set up the username and password in one place.
Update a user

Update a user and return the response.
Expanded list of users api call

When calling /users, we want to be able to provide detailed information. Therefore it's important that we can return the data dynamically, but also provide a way to get typed access to that data should it be required.
Merge branch 'master' of https://github.com/sgrassie/csharp-github-api