Drop support for python 2.6 and django 1.4
Drop support for python 2.6 and django 1.4

ellmetha/django-phonenumber-field,hwkns/django-phonenumber-field,stefanfoulis/django-phonenumber-field,thenewguy/django-phonenumber-field,invalid-access/django-phonenumber-field,hovel/django-phonenumber-field,hovel/django-phonenumber-field,bramd/django-phonenumber-field,thenewguy/django-phonenumber-field,ellmetha/django-phonenumber-field,hwkns/django-phonenumber-field,bramd/django-phonenumber-field,thenewguy/django-phonenumber-field,invalid-access/django-phonenumber-field