Added support for providing a custom params dict
This has been a long outstanding feature request for tlarsen, luckily
it turned out to be very easy to implement with the dict.merge
utility method. To have custom _rights one should instead to the
required access checks before calling the view method.
from django.dispatch import Signal
request_started = Signal()
request_finished = Signal()
got_request_exception = Signal(providing_args=["request"])