Refactor RateLimiter so that if Redis is not running, everything still runs normally (minus the rate limiting protection). My assumption that creating a Redis connection would throw an exception if Redis wasn't running was wrong. The exceptions actually occur when you issue a command. This is for #224.

"""
Urls for the core application.
"""
from django.conf.urls.defaults import *

urlpatterns = patterns('core.views',
    url(r'^markdown_help/$', 'markdown_help', name='core-markdown_help'),
    url(r'^ajax/users/$', 'ajax_users', name='core-ajax_users'),
)