Adding Flask login freindly methods to user model

* Adding flask friendly model to user model
* Deleting shit from all models
Inheriting User model from UserMixin Flask login

making User model class sub class of Flask login's User Mixin class
Modifying get methods for UserDAO

* Adding get method by id
* Modifying get method by email
Adding flask-login integration

Now the flask app can handle user login & logout functions