Merge pull request #22 from sharoonthomas/develop

Refactor and clean cart
Release version 3.0.2.0
Merge branch 'release/3.0.2.0' into develop
Bump version to 3.0.3.0dev

- makes an explicit dependency on trytond_nereid>=3.0.4.0
Use trytond_nereid translation engine
Updates for nereid 3.0.4.0

* Uses current_user and current_user.is_anonymous()
* Uses the login signal from flask-login