- Renamed assertions in the View to better reflect their scope.

* assertResponseHasRedirect => assertViewRedirects
* assertResponseHasNoRedirect => assertViewRedirectsNot
* assertResponseRedirectsTo => assertViewRedirectsTo
* assertResponseHasContentType => assertViewSetsContentType
* assertResponseHasHeader => assertViewSetsHeader
* assertResponseHasCookie => assertViewSetsCookie
* assertResponseHasHTTPStatus => assertViewResponseHasHTTPStatus
* assertResponseHasContent => assertViewResponseHasContent
* assertForwards => assertViewForwards

- Changed the unit tests accordingly.
- Made the message in assertHasLayer() configurable by the user

fixes #1027