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>
Coverage: code coverage testing for Python
Coverage.py is a Python module that measures code coverage during test execution.
It uses the code analysis tools and tracing hooks provided in the Python standard
library to determine which lines are executable, and which have been executed.
For more information, see http://nedbatchelder.com/code/modules/coverage.html