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.
A list of bugs is available in the Google App Engine SDK project on Google Code.
Please visit http://code.google.com/p/googleappengine for more details.