Port to django-fluent-utils, share code for app loading
Fix Django 1.7 warnings

- use get_queryset() in models
- use get_queryset() in admin, moved to django-fluent-utils
setup.py: need newer releases for Django 1.7 compatibility

especially django-parler, as it has a fix for the TranslatableModelForm,
which raises system check errors otherwise (form does not inherit BaseModelForm)
Update example project to avoid errors on Django 1.7
Add Django 1.7 migrations / south_migrations

Provide checks in `__init__.py` to help developers migrate their app to Django 1.7
Fix picture migration, avoid AnyUrlField reference
Compile message changed in 1.7
initial migrations for plugins
Six and Future upgrade
Merge pull request #39 from g3rd/django17

Django 1.7
Merge branch 'django17'
Update changelog about Django 1.7 support
setup.py: enforce latest stable releases with bugfixes