Jinja2 integration if possible

Support django-jinja 1.0.4, coffin 0.3.8, both. Pull Request for #25

Primary library is coffin. Sencondary library is django-jinja.
(Cannot use both at same time. These are occur confliction.)

If python3 env, coffin is disabled. coffin is not python3 compatible library.
But django-jinja is compatible library.