Django 1.6 support.

 * remove AdminMediaHanlder
 * use socket.error instead of WSGEServerException
 * move testproject's "locale" dir to testapp
 * fix manage.py of test projects
 * fix collision for "-p" options between Django and nosetests
In Django 1.6 must calls set_urlconf(None) so that changes of settings.ROOT_URLCONF works.