fixed warning caused by django 1.5 update

I just changed the urls.py file to replace the deprecated

    django.conf.urls.defaults 

with 
    
    django.conf.urls 

as found in the warning message.  Here's the relevant code from ..defaults.py:

    import warnings
    warnings.warn("django.conf.urls.defaults is deprecated; use django.conf.urls instead",
              DeprecationWarning)

    from django.conf.urls import (handler403, handler404, handler500,
        include, patterns, url)


Hopefully this isn't considered too trivial, it's my first pull request, be gentle.