Added tests and fixes

This poor project seems to be languishing.  We would like to start using it in production so I have given it a bit of attention:

* I reorganized the code
* I added tests for the current ArrayField classes
* I fixed the DateFieldArray, as well as lookups for the other fields
* I updated the documentation
* I added an AUTHORS.txt file

I also took the liberty of reformatting the docs and assigning a new version number.

I have no problem pulling from my fork on github into production environments, but it would be great to have these changes integrated back upstream and released on pypi.