Minor example improvement: support (json, status)

- Very minor tweak to the import order (separating stdlib from
  non-stdlib)
- Allow a tuple of size 2 with an int in the second slot to
  trigger special handling

Technically you could use a schema which supports dumping tuple
values, so this really isn't any better or worse than not handling
this case. But it's just an example to show what sorts of things you
can do, so this may be useful for some users.

closes #888

examples/schema_example.py

@@ -14,9 +14,9 @@
     $ http GET :5001/users/ limit==1
 """
 import functools
-from flask import Flask, request
 import random
 
+from flask import Flask, request
 from marshmallow import Schema, fields, post_dump
 from webargs.flaskparser import parser, use_kwargs
 
@@ -74,6 +74,11 @@ def wrapped(*args, **kwargs):
             # Function wrapped with use_args
             func_with_args = use_args_wrapper(func)
             ret = func_with_args(*args, **kwargs)
+
+            # support (json, status) tuples
+            if isinstance(ret, tuple) and len(ret) == 2 and isinstance(ret[1], int):
+                return schema.dump(ret[0], many=list_view), ret[1]
+
             return schema.dump(ret, many=list_view)
 
         return wrapped