baked: Support initial args for cache key

When making baked query in classmethod of declarative base,
cls should be added in cache key.

    @as_declarative
    class Base(object):

        @classmethod
        def baked_query(cls):
            return bakery(lambda: session.query(cls), (cls,))

lib/sqlalchemy/ext/baked.py

@@ -49,8 +49,8 @@ class BakedQuery(object):
 
         _bakery = util.LRUCache(size)
 
-        def call(initial_fn):
-            return cls(_bakery, initial_fn)
+        def call(initial_fn, args=()):
+            return cls(_bakery, initial_fn, args)
 
         return call