Fix #549 -- Multiple PDF ticket layouts (#938)

- [x] Data model
- [x] CRUD
- [x] Editor
- [x] Migration from old settings
- [x] Clone files when copying events
  - [x] badges?
- [x] Actual ticket output
- [x] Default layout on event creation
- [x] Link well from ticketing settings
- [x] Tests
- [x] Shipping plugin
  - [x] Migration
  - [x] Settings
  - [x] Create default
- [x] API

src/pretix/plugins/badges/urls.py

@@ -1,5 +1,8 @@
 from django.conf.urls import url
 
+from pretix.api.urls import event_router
+from pretix.plugins.badges.api import BadgeLayoutViewSet
+
 from .views import (
     LayoutCreate, LayoutDelete, LayoutEditorView, LayoutListView,
     LayoutSetDefault, OrderPrintDo,
@@ -19,3 +22,4 @@ urlpatterns = [
     url(r'^control/event/(?P<organizer>[^/]+)/(?P<event>[^/]+)/badges/(?P<layout>\d+)/editor',
         LayoutEditorView.as_view(), name='edit'),
 ]
+event_router.register('badgelayouts', BadgeLayoutViewSet)