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
Merge pull request #24 from sharoonthomas/develop

Updates for nereid 3.0.4.0
Bump version to 3.0.3.0dev1
Use flask_wtf Form object for cart
Merge pull request #25 from sharoonthomas/develop

Use flask_wtf Form object for cart
Return LazyRenderer objects with view_cart

* It is required if downstream modules should be able to update the
  response context.
* Update dependency onf nereid 3.0.4.2 since the patch uses the
  capability in 3.0.4.2 to update headers in LazyRendered response
  objects
Merge pull request #26 from sharoonthomas/develop

Return LazyRenderer objects with view_cart
Release version 3.0.3.0
Merge branch 'release/3.0.3.0' into develop
Travis can use python-lxml apt package #3907
Fixed flake8 issues
Merge pull request #31 from aroraumang/flake8ify

Fixed flake8 issues
Merge pull request #28 from param107/feature/task-3907

Travis can use python-lxml apt package #3907
Fix NoneType error when trying to update cart quantities
Merge pull request #30 from pokoli/fix_update_cart

Fix NoneType error when trying to update cart quantities
Moved _add_or_update method from cart to sale #4366

Added depreciation warning in cart._add_or_update