Add comments.
Remove client from Request struct.
Upload images in binary format instead of base64.
Use code authorizer in code example.
Make basicResponse internal. Rename Request to Requester.
Let requester create authorizers internally.

- The Authorizer struct can now mostly be hidden from users, except when
setting auth data from previous sessions. Creating a function to do this
should let us hide the Authorizer struct completely from the user.