Update setup.py

including django ver. ​​1.5

"""
https://travis-ci.org/django-debug-toolbar/django-debug-toolbar/jobs/5305231
...
Searching for django>=1.3,<1.5
Reading http://pypi.python.org/simple/django/
Reading http://www.djangoproject.com/
Reading http://www.djangoproject.com/m/bad-installer.txt
Best match: Django 1.4.5
"""