Add a repr implementation for models to make Django template debugging easier.
Add a repr implementation for models to make Django template debugging easier.

Patch contributed by Teemu Kurppa. Thanks.

Fixes Issue #67.

ekkleesia3/google-app-engine-django,google-code-export/google-app-engine-django,hitrust/google-app-engine-django,termie/google-app-engine-django,dila93/google-app-engine-django,jackxiang/google-app-engine-django,brian-zhao/google-app-engine-django