Include the field_id in the context of _as_table_helper
This makes it possible to refer to the field that is being edited by
it's ID (in for example Javascript).
Patch by: "Mario Ferraro" <fadinlight@gmail.com>
import os, sys
sys.path.insert(0, os.path.dirname(os.path.dirname(__file__)))
import pkg_resources
pkg_resources.require('WebOb')