Add support for prefetching fields This makes it possible to specify the fields that should be prefetched as part of a getForFields query. Doing a prefetch on a ReferenceProperty when it is known that the property will be referenced in (almost all) entities is far more efficient than doing the invididual fetches sequentially.

#!/bin/sh
NOSE_WITH_DOCTEST=t
export NOSE_WITH_DOCTEST
NOSE_DOCTEST_EXTENSION=txt
export NOSE_DOCTEST_EXTENSION
#NOSE_DETAILED_ERRORS=t
#export NOSE_DETAILED_ERRORS
nosetests $*