Update pytest to 3.3.0

Update pytest to 3.2.5

Update jinja2 to 2.10

Update flake8-debugger to 3.0.0

Update sqlalchemy to 1.1.15

Update psycopg2 to 2.7.3.2

Update flake8-quotes to 0.12.0

Update flake8 to 3.5.0

Update webtest to 2.0.29

Use `FlaskForm` instead of deprecated `Form`.

https://flask-wtf.readthedocs.io/en/latest/api.html#flask_wtf.Form

Deprecate pytest yield fixtures.

https://docs.pytest.org/en/latest/yieldfixture.html

Update flask-sqlalchemy to 2.3.2

Update pytest to 3.2.3

Update flask-sqlalchemy to 2.3.1

Update pytest to 3.2.2

Update sqlalchemy to 1.1.14

Update flask-migrate to 2.1.1

Update sqlalchemy to 1.1.13

Update factory-boy to 2.9.2