Update README.md

Updated description.
Update README.md

Added screen shot of login page.
JsonLogin request handler #3
Merge branch 'json-api' of github.com:roberthodgen/ndb_users into json-api
JsonLoginCreate request handler #3
Update comment
JsonLoginActivate request handler #3
JsonLoginPasswordChange request handler #3

Also corrected issue in JsonLogin where `response_object` was called on `self` (shouldn't!)

Added `Content-Type` headers where they were previously missing.
JsonLoginPasswordForgot request handler #3
JsonLoginPasswordReset request handler #3

Also fixed issue in users.UserSession.create_user_session() where **kwargs was missing (appeared to have issue with @classmethod decorator?)
Update README.md

Removed JSON API todo.
JsonLogin sends empty user on logout
Merge branch 'json-api' of github.com:roberthodgen/ndb_users into json-api
Half of docs updated #18
JSON API docs draft #18
Merge pull request #19 from roberthodgen/json-api

JSON API implemented