http_exceptions must be a tuple, not a list
Added auto-set properties on DynamoModel of "created_at" and
"modified_at", both which are called through a convinient function
"on_save_or_update", which is called for both a put() and a save()
operation, making it very easy to also do other operations such as
setting other properties automaticaly on save (for example you could
maintain a version number which is increased with each save or update).
Added support for specifying an output format on any property, including
strings and blobs, so you can specifically tell us to format the string
output as XML.

This helps when looking up files from something that you know the format
is XML, so it reports the appropriate content type and lets browsers
display it properly.
Improved logging on OID authentication, and make sure that only Google
OID is trusted for email-based authentication
added an "after_save_or_update" function that is automatically called
after the save or update operation was successfully completed.
Added put_attributes to dynamo items, to make them consistent with
regular models
Added expected_value and return_values options to put_attributes
Added a quickfix to ignore any tuple values for properties. This is how
some values are returned from DynamoModels, which needs to eventually be
fixed.
Added work-around logic for NewRelic error reporting
Fixed to send proper traceback object to newrelic exception reporting
Fixed user cache logic to FIRST try local cache, and then to /try/ to
use the memcached option
Added request limit option to dynamodb models