Fixing CORS support (#1200)

* Add `*args` and `**kwargs` to options function signature

* Add `POST`, `GET` and `PATCH` to the Access-Control-Allow-Methods header

* Add `access-control-allow-origin,authorization,content-type` to the allowed headers list

flower/views/__init__.py

@@ -17,11 +17,12 @@
 class BaseHandler(tornado.web.RequestHandler):
     def set_default_headers(self):
         self.set_header("Access-Control-Allow-Origin", "*")
-        self.set_header("Access-Control-Allow-Headers", "x-requested-with")
+        self.set_header("Access-Control-Allow-Headers",
+                        "x-requested-with,access-control-allow-origin,authorization,content-type")
         self.set_header('Access-Control-Allow-Methods',
-                        ' PUT, DELETE, OPTIONS')
+                        ' PUT, DELETE, OPTIONS, POST, GET, PATCH')
 
-    def options(self):
+    def options(self, *args, **kwargs):
         self.set_status(204)
         self.finish()