PYCBC-158: Add 'no_format' argument to get

This is a localized form of 'data_passthrough'

Change-Id: I38908a7e0b0bdaea0d6f38c5ccab04d0a1b9766d
Reviewed-on: http://review.couchbase.org/27623
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>