If no defaults no need to loop
Support for binary fields using gridfs
Let choose if use gridfs or not

* Now you can use `gridfs=True` in fields.binary in osv_mongodb
* Renamed funciontos to binary_gridfs
Support for a gridfs field

With this you can mix a postgresql model with binary fields stored
in MongoDB.
The postgresQL field is a char with size 24 to store the ObjectId,
and the content is stored in MongoDB GridFS.
Support for file versioning
Merge pull request #4 from gisce/no_for_defaults

If no defaults no need to loop
Merge pull request #5 from gisce/gridfs_binary_fields_support

Support for binary fields using gridfs
Merge pull request #6 from gisce/fields_gridfs

Make a fields.gridfs()
Merge remote-tracking branch 'origin/developer'
Version 0.2