Eliminate GenericView

Hopefully I won't waste too much of your time with this, but I'm curious why you chose to have a `GenericView` with form methods that don't apply to the template view as a base view, rather than just having a `TemplateView` and a `FormView` that inherits from the `TemplateView`? It seems like leaving out the `GenericView`, which isn't useful by itself, would be a simpler choice.

The only reason I can see is that the `FormView` has to override the `get()` method defined in `TemplateView`, but that seems straightforward and obvious to me, especially because there's no call to `super()` needed. Real code attached for discussion, though it doesn't pass tests and breaks backward compatibility, so I know you won't want to use this code as-is anyway.