When trying to debug a Heisenbug or to help with testing it can be useful to run without caching enabled. This pull request adds a dummy backend, which allows you to easily disable caching for one or more regions by configuring your app to use this backend.
Dogpile works well enough that it doesn't need much attention :).
For what it's worth: I looked at adding tests for the dummy backend, but I couldn't really think of anything that made sense. Perhaps a trivial fixture that just tests of a backend implements the API correctly but doesn't test behaviour, but that felt like a bit of overkill here. If you do want that let me know and I'll add it.
OK every PR i wanted to put for now is in, I'm working up a release. Since you're online, if you feel like checking out master and beating on it in the next ten minutes, feel free, a couple of redis arguments were also added.