0.06
        - clarify the documentation on how to configure a backend
        - due to stacked evals, certain start up errors were quietly
          ignored until the first cache hit. These start up errors
          now correctly manifest themselves at start up time.
0.05
        - change base class order to appease Class::C3

0.04
        - ???

0.03
        - Be more compatible with ->set() convention of passing expiry

0.02
        - Pass around a hash ref instead of a list of kvp.

0.01
        - Initial release
