Update extension imports to flask_*

See mitsuhiko/flask#1135

{{cookiecutter.app_name}}/{{cookiecutter.app_name}}/public/views.py

@@ -2,7 +2,7 @@
 """Public section, including homepage and signup."""
 from flask import (Blueprint, request, render_template, flash, url_for,
                     redirect, session)
-from flask.ext.login import login_user, login_required, logout_user
+from flask_login import login_user, login_required, logout_user
 
 from {{cookiecutter.app_name}}.extensions import login_manager
 from {{cookiecutter.app_name}}.user.models import User

{{cookiecutter.app_name}}/{{cookiecutter.app_name}}/user/views.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 from flask import Blueprint, render_template
-from flask.ext.login import login_required
+from flask_login import login_required
 
 blueprint = Blueprint("user", __name__, url_prefix='/users',
                       static_folder="../static")