Add support to template_name_suffix in get_template_names methods
Merge branch 'master' of github.com:opps/opps

* 'master' of github.com:opps/opps:
  pep8
  tests fields boxes models
  test fields sources models
  test for fields content in flatpages
  test for fields, flatpages
  write container test template tag get_containers_by, ref #215