_allow_dynamic_properties = False raises bad error for nested schemas

[dannyroberts]

No description provided.

[majutsushi]

The description of this issue rather minimalist, but I'm running into this problem which may be the same issue:

class A(jsonobject.JsonObject):
    _allow_dynamic_properties = False

class B(A):
    foo = jsonobject.StringProperty(required=True)

class C(jsonobject.JsonObject):
    components = jsonobject.DictProperty(A, default={})

c = C()
c.components["test"] = (B(foo="/foo/bar"))
C(c.to_json())

Traceback (most recent call last):
  File "jsonobject/base.pyx", line 202, in jsonobject.jsonobject.base.JsonObjectBase.__init__
  File "jsonobject/base.pyx", line 239, in jsonobject.jsonobject.base.JsonObjectBase.set_raw_value
  File "jsonobject/base.pyx", line 322, in jsonobject.jsonobject.base.JsonObjectBase.__setattr__
AttributeError: 'foo' is not defined in schema (not a valid property)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "jsonobject/base.pyx", line 202, in jsonobject.jsonobject.base.JsonObjectBase.__init__
  File "jsonobject/base.pyx", line 235, in jsonobject.jsonobject.base.JsonObjectBase.set_raw_value
  File "jsonobject/base.pyx", line 274, in jsonobject.jsonobject.base.JsonObjectBase.__wrap
  File "jsonobject/base_properties.pyx", line 180, in jsonobject.jsonobject.base_properties.JsonContainerProperty.wrap
  File "jsonobject/containers.pyx", line 129, in jsonobject.jsonobject.containers.JsonDict.__init__
  File "jsonobject/containers.pyx", line 136, in jsonobject.jsonobject.containers.JsonDict.__wrap
  File "jsonobject/properties.pyx", line 154, in jsonobject.jsonobject.properties.ObjectProperty.wrap
  File "jsonobject/base.pyx", line 251, in jsonobject.jsonobject.base.JsonObjectBase.wrap
  File "jsonobject/base.pyx", line 204, in jsonobject.jsonobject.base.JsonObjectBase.__init__
jsonobject.exceptions.WrappingAttributeError: can't set attribute corresponding to 'foo' on a <class '__main__.A'> while wrapping {'foo': '/foo/bar'}

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./test2.py", line 18, in <module>
    C(c.to_json())
  File "jsonobject/base.pyx", line 204, in jsonobject.jsonobject.base.JsonObjectBase.__init__
jsonobject.exceptions.WrappingAttributeError: can't set attribute corresponding to 'components' on a <class '__main__.C'> while wrapping {'components': {'test': {'foo': '/foo/bar'}}}

Moving _allow_dynamic_properties to the subclass makes it work, but it would be really nice if this attribute didn't have to be set in each "leaf" class.