Django-hijack

- Optional setting for admin hijack button template, cf. http://django-hijack.readthedocs.org/en/latest/configuration/#hijack_button_template
- Minor enhancements

- Use pk to access the User primary key

- Use pk to access the User primary key

- Remove `django-sessioninfo` as a dependency

- Unify settings; Django will show a warning if a deprecated setting name is used. See http://django-hijack.rtfd.org/en/latest/configuration/#settings-overview
- Drop official support for Django 1.4, 1.6; add support for 1.9 using https://github.com/arteria/django-compat v1.0.8
- Add i18n support, see https://github.com/arteria/django-hijack/tree/v2.0.0/hijack/locale
- Make `HIJACK_DECORATOR` configurable
- Do not update last_login time of hijacked users
- Add optional Bootstrap-optimized notification bar. Can be activated with `HIJACK_USE_BOOTSTRAP`
- Add signals `hijack_started` and `hijack_ended`
- Add AppConfig and various checks
- Check "next" GET parameter for safety
- Move documentation to http://django-hijack.readthedocs.org/
- Use https://github.com/arteria/django-sessioninfo as a dependency
- Rewrite tests

- Bugfixes
- Allow hijacking users with negative IDs