Interim changes for adding accessor attribute.
Use attname to allow differentiation of column and accessor.
Declare all fields automatically using contribute_to_class rather than require individual specifications of appropriate fields.
Added tag 0.2 for changeset da0992ba177e
Cleanup, refactoring, documentation.

* Added backport from Django 1.5 of the new MeasurementBase class (beautiful work, @aaugustin).
* Added a readme showing one how to use this functionality.
* Bumped version number to 0.3.
Added tag 0.3 for changeset dd2a35c1445c
Adding manifest.