Fix a bug in duplicate detection
This is caused by AppEngine's inability to sort a query when the
inequality or IN operator is used. See also [0].
[0] http://code.google.com/p/googleappengine/issues/detail?id=1100
Patch by: Sverre Rabbelier and Lennard de Rijk
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