Cleanup in org_app and replace ReferenceProperty with LinkProperty
Using LinkProperty allows the org to host their idea's list on
Melange through the Document system, and then specify the URL of that
document. This also makes it possible for the orgs to specify a
document that is not hosted on Melange.
Patch by: Sverre Rabbelier
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