Migrate to Django 1.8-style URLconfigs

See
https://docs.djangoproject.com/en/dev/releases/1.8/#django-conf-urls-patterns
and #14

src/pretix/urls.py

@@ -1,4 +1,4 @@
-from django.conf.urls import patterns, include, url
+from django.conf.urls import include, url
 from django.contrib import admin
 from django.conf import settings
 
@@ -6,19 +6,19 @@ import pretix.control.urls
 import pretix.presale.urls
 
 
-urlpatterns = patterns('',
+urlpatterns = [
     url(r'^control/', include(pretix.control.urls, namespace='control')),
     url(r'^admin/', include(admin.site.urls)),
     # The pretixpresale namespace is configured at the bottom of this file, because it
     # contains a wildcard-style URL which has to be configured _after_ debug settings.
-)
+]
 
 if settings.DEBUG:
     import debug_toolbar
-    urlpatterns += patterns('',
+    urlpatterns.append(
         url(r'^__debug__/', include(debug_toolbar.urls)),
     )
 
-urlpatterns += patterns('',
+urlpatterns.append(
     url(r'', include(pretix.presale.urls, namespace='presale'))
 )