Don't do silly things like repeat a value
Add a dictionary and a redis backend
Add an API conformation test

Generators are fun!
Docstring fixes
Be smarter about keys
Be smarter about hashing keys
Remove unnecessary docstrings
Test individual backends as opposed to all at once

I used to just test API conformance for all of the backends by finding
all of the BaseBackend subclasses and using a tes generator for each of them.
Now I test the backends individually so we can skip them more intelligently and
see more precisely why they failed.
Add a sane default when an engine isn't specified
Test individual backends as opposed to all at once

I used to just test API conformance for all of the backends by finding
all of the BaseBackend subclasses and using a tes generator for each of them.
Now I test the backends individually so we can skip them more intelligently and
see more precisely why they failed
Merge pull request #34 from iankronquist/more_backends

More backends