Fix get_fallback_languages(), always return a list, never None
Fix get_fallback_languages(), always return a list, never None

This fixes the multi-fallback support introduced by #78
Also fixes any_language features in other calls

imposeren/django-parler,django-parler/django-parler,django-parler/django-parler,ellmetha/django-parler,edoburu/django-parler,imposeren/django-parler,defivelo/django-parler,edoburu/django-parler,skirsdeda/django-parler,skirsdeda/django-parler,zhangguiyu/django-parler,jrief/django-parler,defivelo/django-parler,zhangguiyu/django-parler,jrief/django-parler,ellmetha/django-parler