Port geomodel to the upcoming ndb datastore API

[GoogleCodeExporter]

Google App Engine looks likely to release an improved datastore API called ndb 
[http://code.google.com/p/appengine-ndb-experiment/] in the not-too-distant 
future as part of the official SDK.

ndb offers a number of benefits - particularly relating to performance and 
executing queries asynchronously.

My app already uses ndb instead of db, and I also plan to use geomodel. For now 
I'm going to port the current version of geomodel to ndb myself, but it would 
be awesome if the geomodel project could be made ndb-compatible so that 
developers like myself can benefit from future updates.

Original issue reported on code.google.com by [email protected] on 5 Sep 2011 at 8:26