Make it possible to retrieve all properties in toDict
We used to retrieve only the properties that are specified in the
self.properties() dictionary, instead, we now iterate over the
key_fields and only use self.properties() if those are not specified.
Patch by: Sverre Rabbelier
from django.dispatch import Signal
request_started = Signal()
request_finished = Signal()
got_request_exception = Signal(providing_args=["request"])